Full Frame Lenses on Crop Sensor Cameras Don't Work the Way You Think They Work

[@camelliama6490]

This is the clearest comparison and analysis of full frame sensor and APS-C I've seen. Thank you so much! Great examples and explanations! ❤👍

[@thephotographytoolkit]

Thanks so much Camellia. I am so happy that it was really clear and helpful.

[@Lee-BKK]

Definitely agreed. Thanks!

[@fastidioussloth6013]

Ditto.

[@imhorsenaround]

FINALLY!! I have been looking for an explanation like this for years! You are the only person who actually SHOWS this instead of just telling. Thank you!

[@thephotographytoolkit]

I really appreciate your comment. I completely understand the value of seeing something! To be totally honest, I couldn't just accept something that I had been told and tell others the same thing. I had to try it out for myself for myself and actually see it. When I first compared the pictures, it made so much more sense and I could actually see the difference instead of trying to imagine it. Thanks again!

[@001jbs]

I have also been looking for an explanation with illustrations like this. So thank you very much.

[@VR_Wizard]

​@@thephotographytoolkit To meke the explaination even better it would have been nice to explain the physiks of light behind it as well. Intuitively one would imagen taht putting a full frame lens on a crop sesor camera would let much more light in even if the aperature is higher. But your video showed the exact opposite. I thing it has to do with the bigger sensor collecting all the light and the crop sensor only collecting a fraction of the light comng in but I dont understand all the details yet. I am still looking for a good answear to that. Anyway thanks for the video.

[@thephotographytoolkit]

@@VR_Wizard I hope this explanation makes sense. When you put a lens on a camera, a circle of light is projected onto the camera's sensor. When that lens is a full frame lens, the circle of light will be large enough to cover all the edges of the 24mm x 36mm full frame sensor. There are parts of the circle that don't hit the sensor. When you put that same full frame lens on a crop sensor camera, the same amount of light comes through that lens as it would if it were on a full frame camera. The amount of light coming through the lens doesn't change. The circle of light from that lens is the same size, it is just being projected onto a smaller cropped sensor (16mm x 24mm for a Nikon camera). If you have a piece of paper and a flashlight you can create an example of what I am talking about. Stick a piece of paper (which represents your full frame sensor) to a wall and shine the flashlight (representing the light coming through your lens) onto the paper. Make sure the light covers all 4 corners of the paper. Don't move the flashlight. Now draw a smaller rectangle on your piece of paper that is about 2/3 the size of the paper. That represents the cropped sensor. The same amount of light is coming through the lens; it is just that less of that light is hitting the sensor. The video at the bottom of this page may help illustrate what I am trying to say: www.nikonusa.com/en/learn-and-explore/a/products-and-innovation/the-dx-and-fx-formats.html

[@VR_Wizard]

​@@thephotographytoolkit Your explanation makes sense but I still dont understand why the apperature changes by simply using another sensor. You make a calculation in the video and the result shows it is a different f value and images show it too but the physics behind it are not clear to me. I dont know why that is what happens to the light rays to result in a differen bokeh effect.

[@martineden8389]

Finally a video that illustrates that multiplying the focal length by the aps-c crop factor does not produce the same amount of perspective distortion when it's applied on full frame. In other words, 18mm on an aps-c might have the same angle of view as 24mm on full frame, but the two images will feature different flatness of perspective typical of their respective focal lengths

[@thephotographytoolkit]

Thanks so much Martin.

[@mynameisben123]

How can it have different perspective distortion? Perspective distortion only depends on the position of the camera. It doesn’t depend on focal length or sensor size.

[@thephotographytoolkit]

@@mynameisben123 You are correct that sensor size doesn't affect distortion. However, focal length does affect distortion. If I use a 14mm wide angle lens and a 50mm lens from exactly the same position, the distortion will be different. This is especially true when something is close to the camera. You can see the difference in this part of my video: kzbin.info/www/bejne/pF7ag2R8n7yLidU

[@okaro6595]

No, the perspective is the same. The difference was because he chose a very wide angle lens and shot close when the optical center did not remain at the same location. How could the prospective be different if the angle of view and distance are the same?

[@martineden8389]

@@okaro6595 perspective distortion

[@TheFrancis2048]

Wow great, I’ve been looking for this explanation regarding the aperture values and how they change having just bought an aps-c viltrox 27mm1.2 for my full-frame sony

[@thephotographytoolkit]

I'm glad the video was helpful.

[@LTE18]

Thank you.. finally a person that speaks about change in perspective when on a different sensor size camera. I have never heard anyone mention this in all of these "why you should get xxx frame camera" videos

[@thephotographytoolkit]

Thanks for the comment. I am glad it was helpful.

[@JackBeasleyMedia]

Thanks for demonstrating the 200mm looking the same on a DX camera as it does when cropped in post from a FX camera. I've had that argument way too many times with people who claimed there was a difference.

[@thephotographytoolkit]

Happy to help. You are absolutely right. Crop (DX) sensor is just a crop of a full frame sensor when both have the same lens.

[@JimSamuel267]

I just saw this video and am happy to see someone on KZbin get this right. Too many people think that a 100mm lens is the equivalent of a 160mm lens when you put it on an APS-C camera. Thanks for getting this correct.

[@thephotographytoolkit]

Thanks Jim. Like you, I have come across too many people who misunderstand what happens when you use a full frame lens on an APSC camera and that is why I made the video. I am glad it was correct.

[@FeedScrn]

I really like how you took the time to put in alternating photos for comparison. I think that you were the only one who did this in all the FF / APSC and crop factor videos.

[@thephotographytoolkit]

Thanks so much! I really enjoyed doing the comparison as it helped me to better understand the differences.

[@interdec]

Yeah; this subject was originally covered by Tony & Chelsea Northrup some years back. They too failed to make it clear that although the depth of field will not be the same, the exposure most certainly is: Viewers, the aperture is exactly what it says on the lens, so don’t go thinking you have to alter your exposure by any crop factor. The depth of field will be different simply because to achieve the same size image of the same subject, your camera to subject distance will be different, and therefore your focus distance will be different. This is not an issue, it’s just a difference. Remember, “full frame” is a misnomer, simply referring to a sensor size the same size as a 24x36mm shot from a “full frame” on 35mm film. That though, is really the equivalent of a crop from a medium format sensor, which is still not the real deal, because that is a crop from a larger “plate” film. And so on, etc. To sum up, I believe the easiest way to think of this would be to say that “in order to achieve a similar depth of field effect using a full frame lens on a crop sensor camera you would also need to multiply the aperture by the crop factor. NOT for exposure, just for depth of field comparison.” This makes things sound too complicated though, and I suggest just take the shot as you normally would, look at it, and adjust your aperture as necessary to achieve more or less depth of field”. My point is that this and the Northrup video is introducing a complexity where none exists.

[@thephotographytoolkit]

Thanks for the comment. You are absolutely correct that the exposure doesn’t change when you use a crop sensor or full frame sensor. As you are aware, and as I mention in my video, a crop sensor is just a crop of a full frame. So, to me, it makes sense that the exposure doesn’t change. And that is maybe why I didn’t mention it - because I thought it was obvious. I guess I could have been more clear as to all the aspects of crop sensor vs full frame including exposure. To be completely honest, exposure isn’t the thing that people get confused about because they can see for themselves that it doesn’t change. What photographers do often get confused about is the focal length of a full frame lens when it is put on a crop sensor camera. Many photographers think that a full frame 200mm F4 lens on a crop sensor camera IS a 300mm F4 lens. But if you put a 200mm F4 lens on a crop sensor camera and compare it to a 300mm F4 lens on a full frame camera (both in exactly the same spot) the images will be different. The 300mm F4 lens will have a blurrier background. You can see the difference in this part of the video: kzbin.info/www/bejne/pF7ag2R8n7yLidU You said “The depth of field will be different simply because to achieve the same size image of the same subject, your camera to subject distance will be different, and therefore your focus distance will be different.” However, in my examples, the camera has NOT moved. I have the SAME camera to subject distance. I have the SAME focus distance. What has changed in the focal length of the lens and the size of the sensor. So a 14mm lens on a crop sensor camera will have a different look than a 21mm lens on a full frame sensor camera even though they have equivalent focal lengths and are captured from exactly the same spot. You can see the differences at this part of the video: kzbin.info/www/bejne/pF7ag2R8n7yLidU You also said “I believe the easiest way to think of this would be to say that ‘in order to achieve a similar depth of field effect using a full frame lens on a crop sensor camera you would also need to multiply the aperture by the crop factor.’” I did say this when explaining equivalent apertures here: kzbin.info/www/bejne/pF7ag2R8n7yLidU At the end of the day, what I was trying to demonstrate in this video was that even though a crop sensor camera gives you a longer equivalent focal length (ex 200mm x 1.5 = 300mm), the image will not look the same as an equivalent full frame focal length lens (in this case 300mm) on a full frame camera captured from exactly the same spot. I wasn’t attempting to demonstrate anything to do with exposure simply because the exposure doesn’t change. Thanks again for your comment.

[@okaro6595]

Maybe they did not make it clear to you but they did to me. Just because you do not get something does not mean it is wrong. Yes the aperture does not change anywhere but neither does the focal length. The point in their videos were that you have to use the equivalence on all three: focal length, aperture and ISO if you use it. Now in practice when I shoot my G9 X I do think the equivalent focal length but never the equivalent aperture but then I do not consider things like bokeh. It is not a tool for such use.

[@interdec]

@@okaro6595 On the other hand, aperture is the main tool to control and adjust background blur, so not quite sure what you mean.

[@CarmineTavernaPhotography]

After 50 years as a photojournalist, I found your video very important and well done, Bravo David

[@thephotographytoolkit]

Thanks so much Carmine! I really appreciate the comment!

[@matthieuzglurg6015]

although your video is 100% correct, there is something I would want to add to your video, which a LOT of beginners get wrong talking about equivalent apertures and focal length. The change in background blur is tied to 3 things : the focal length (the logner it is, the shallower the DOF is), the focusing distance (the closer it is, the shallower the DOF is), and the aperture (the wider it's opened, the shallower the DOF is). Calculating the equivalent aperture is basically the same thing as emulating what lens you WOULD need on a full frame camera to reproduce the exact same image, with the same depth of field and background blur. For example, when going from 300mm to a 4500mm equivalent focal length using the same lens but smaller sensor, the equivalent aperture is smaller, because a "real" 450mm lens, due to its longer focal length (and wider aperture, that's tied to the focal length anyway) would have a shallower depth of field and a blurrier background than a 300mm lens opened at teh same aperture, therefore we need to close it to match. BUT A lot of people are taking this too literally. The quantity of light delivered by the lens is a matter of density of surface (amount of photons per unit of surface), meaning that this varies the exact same way on the whole image circle of the lens as you change the aperture. The pixels of an APS-C sensor will recieve the same amount of light as the pixels of a full frame sneos, only difference is that on the full frame camera there is more of them, on a larger area. What this blabber means is that it's not because you change the format of the sensor that you suddenly get less light. An F/4 lens will have the same exposure throughout the whole sensor, no matter if it's full frame or APS-C. The confusion people make with the equivalent aperture is that it reduces the amount of light you get, because instinctively "f/6 is less light than f/4". Except it DOESN'T have anything to do with exposure, it's all just a matter of depth of field and trying to match the redition of the image. Exposure has NOTHING to do with it, yet I still see people around the internet convinced that you get more light and a brighter exposure on a full frame camera. You don't.

[@thephotographytoolkit]

Thanks so much for your comment. I totally agree with everything you have said. I understand that when someone hears an equivalent aperture of F6 they might think that there is less light than F4. The key is for these people to fully understand that equivalent doesn’t mean actual. And like you said, it doesn’t matter if it is APS-C or full frame - there is the same amount of light hitting the sensor. Thanks again for sharing.

[@professionalpotato4764]

False, changing formats does reduce the total amount of light. You get the same exposure (i.e. light/m^2), but the total signal obtained is different due to difference in photons captured. The equivalent aperture not only denotes the expected DoF comparison, but also ISO performance across sensor formats. E.g. APSC = 1 stop less, MFT = 2 stops less. You can even look up Matteo Sulanto's video where the compared the noise performance across different formats. The following images will have the exact same amount of noise and about the same DoF. Full frame at ISO 1600, f6 APSC at ISO 800, f4 MFT at ISO 400 f3.2 If things were so magical and the change in sensor format doesn't affect the image, we would be printing Nat Geo worthy Milky Way shots from an iPhone.

[@okaro6595]

The formula for depth of field is: D = s / (1 ± N × 0.03 / c × (1000 × s - f) / f²) s: the distance (meters) N: the aperture value c: the crop factor f: the focal length (mm) Where 0.03 mm is the acceptable circle of confusion on full frame. The + gives the near limit and the minus the far limit (if negative or division by zero then it is infinity). The crop factor affects but it is not in the direction people think. With same focal length and distance the depth of field on smaller sensor is less as the image is magnified more. (Note the subject of course cannot be same. The subject is not relevant. Your cat is not in the formula) What people do not get that there is a third component: equivalent ISO. For the simplicity lets assume the crop factor is 2 and the sensor is 3:2 (I know there are no such sensors but this is just an example): 50 mm f/4 ISO 200 is equivalent to 100 mm f/8 ISO 800. These would produce very close to identical results. Note on equivalent ISO one has to use the crop factor squared.

[@9Mtikcus]

Just came across this video/channel Hit the sub button, as a professional photographer I think you have explained it well, I would add just 2 things when comparing different sensor sizes the Aperture effects Depth of Field, where Exposure remains the same F/4 is F/4 weather you are shooting on "Full Frame" or Large Format. but it is explained well (I'd just change the wording to Depth of Field) The way I have tried to explain it is for example, a 56mm F/1.4 on a Crop camera, gives you the eqv. angle of view as an 85mm on a full frame camera but the depth of field of a 56mm F/1.4 on a full frame camera. And a rule of thumb (not exact, but no calculator required) if you want the equivalent DOF of a full frame camera, you need to use a lens 1 stop faster on a crop sensor, 2 stops faster on M4/3, and 1 stop slower on Digital medium format (e.g. Fujifilm GFX)

[@thephotographytoolkit]

Thanks so much for the comment and for subscribing Andrew! Also thank you for the recommendations for improvements.

[@CinePals]

This answered the exact question I was asking. The new Sony ZV-E1 dropped and I have a 14mm 1.8. Wondered if I could use that 14mm instead of my Samyang 18mm or Sony 20mm, but this video helped illustrate that it's probably best to go with the longer lenses for vlogging. Thought maybe I could use the 14mm and zoom in as needed to avoid distortion, but this video illustrated to me that's certainly not the case as the distortion will still remain, you'll just see less of it in the crop.

[@thephotographytoolkit]

I am really happy that the video answered your question!. Thanks so much for the comment.

[@whitelion204]

2:04 Comparing the 14mm and the 21mm on the same FF sensor is NOT the same as comparing 14mm FF to the 21mm crop. The difference in perspective is not due to the actual focal length, but instead how far/close the camera is to the subject. Since you're comparing 14mm and 21mm on the same FF sensor, you have to move further away from the subject with the 21mm, thus the perspective change. On the other hand, if you have a 21mm crop lens you will have the same perspective as the 14mm FF because you would stay on the same spot.

[@thephotographytoolkit]

Thanks for the comment. I am not totally sure I understand what you are trying to say. But I just want to clarify a few things. First of all, the point of my video is that you can't just multiply the focal length of a full frame lens when you put it on a APSC camera and get the same image as you would on a full frame sensor. Many photographers I have talked to think that you will get the same image but you won't. Secondly, the images of the 14mm FF lens on an APSC sensor camera is captured in from exactly the same place as the 21mm FF lens on a FF sensor at 2:04. I haven't moved at all in any of the comparison photos. The whole point is to not move my camera further or closer away. That changes what I am trying to demonstrate. Thanks

[@whitelion204]

Ah okay, sorry I was not familiar with the Nikon's DX FX system, so I thought it was the 14mm a FF sensor. I think the reason the 14mm on ASPC looks a little bit different is because of the lens distortion. Have you tried corrected the image in post? Lenses have nothing to do with perspective warping, it's the distance from the camera that matters.

[@thephotographytoolkit]

@@whitelion204 Thanks for the response. You mention lens distortion and correcting the image in post. But I am not sure how I would do that. The 14mm on an APSC sensor and the 21mm on the full frame sensor at 2:04 look very different even though they are captured from the exact same spot. The blur in the background is very different and the position of the plant and the building compared to the foreground subject are different. Is that something that could be corrected in post? That doesn't seem possible to me. Thanks

[@whitelion204]

@@thephotographytoolkit I looked at the photo on the 14mm again, and I'm pretty sure there's a barrel distortion going on. You can go to the Lens Corrections section in LR (or Capture One) and correct in manually. If you're unable to do that, I suggest you do the comparison again but on longer focal length, such as 50mm or longer, since on the long end there will be much less lens distortion. About the depth of field - you are correct. Since you're effectively using a shorter focal length on the APS-C, the DOF would be thicker and the bokeh would be less blurry. But other than that - there should be no difference.

[@thephotographytoolkit]

@@whitelion204 Thanks for the reply and for sharing your thoughts Duy.

[@hansfijlstra5932]

Excellent video! However, I believe ‘f’ stands for focal length and not for fraction. That’s why the brightness of a lens is always written as a fraction of the focal length divided by the aperture number. For example f/4.0. With a 200mm focal length, the actual lens opening is 200/4 = 50mm. Although nowadays the division sign is often omitted.

[@thephotographytoolkit]

Thanks for the comment. Fair comment about the 'f' standing for focal length. I was taught that 'f' was f-ratio and a ratio is a fraction. I liked f-ratio (fraction) better and focal length because it made sense to me. So an aperture of F4 on a 200mm lens is 1/4th of 200mm which is 50mm. Calling 'f' focal length never really made sense to me but you have explained it well. Thanks again!

[@jasonbodden8816]

@@thephotographytoolkit Well, the whole formula is *diameter of the lens opening = focal length/number.* (hence, the reason it's typically written as f/number. I prefer it written this way as the division sign shows it's a fractional value right off the bat). So it makes more sense than "fraction" when you know what the f represents in the formula. You can see why it stands for "focal length" and not "fraction." And Fraction/4 wouldn't make sense anyhow lol.

[@thephotographytoolkit]

@@jasonbodden8816 Thanks for the clarification.

[@MyPianoArchives]

You’re a great teacher - finally I understand why my canon rebels look so zoomed.

[@thephotographytoolkit]

Thanks so much for the kind comment. I am glad it was clear.

[@91111001]

This is the exact explanation im looking for after years of misunderstanding

[@thephotographytoolkit]

Yay! I'm so glad that you found it and it was helpful.

[@TheKocton]

The best video I have found about this topic! I need this to really understand the focal length equivalence. Thanks a lot!!!

[@thephotographytoolkit]

I am so happy that it has helped you to understand focal length equivalence. You are very welcome. Thanks so much for the comment!

[@DenBlackburn]

Ive watch so many video on full and cropped, everone explains the 1.5 for mm, but this is the first ive ever seen that lets you know about the f/stop. Fantastic, thanks for clearing that up, thats really helped me a lot, and yes the are not the same but as close as im going to get, thanks for your time and effort on explaining that, it now makes a lot of sense.

[@thephotographytoolkit]

Thanks so much for the comment Den. I am really happy the video helped to clear things up!

[@JAF2991]

GREAT EXPLANATION! Got it now, I was always assuming APSC cameras "zoomed in" so if you have a 35 it'll act like a 50. When it only crops it, thereforeit is only "looking" like a 50 in terms of FOV or angle of view.

[@thephotographytoolkit]

Thanks so much! You have got it exactly!

[@bernym4047]

Excellent treatise on crop sensor lens characteristics. Thank you.

[@thephotographytoolkit]

Thanks Berny

[@alfredchiu1925]

The first video which I know of that addresses the perspective changes. Nice on that. I wish/try to add a bit more here. The perspective difference is more noticeable if the subject distance is very close or shorter than the focal length. This is because the 1.5x focal length, which is actually an approximation, only works on the assumption that the subject distance is much larger than the focal length in the magnification ratio equation. This whole approximation breaks down if subject distance is very close to the focal length. Look at the comparison of 200mm on crop sensor vs 300mm on ff and you won't notice that much difference compared to the 14 vs 21mm case. I've learned the maths, I know the phenomenon, but this is the first time I saw it. Nice.

[@thephotographytoolkit]

Thanks so much for the in depth comment!

[@I_am_cooked_For_Life]

You did an excellent job explaining it, thank you! Indirectly, this also explains why we’re unlikely to see FF lenses any smaller than they are now unless we find a way to bend the laws of physics. If I had to make any suggestions for your future videos, I think it would be better if you put the photos side by side so viewers can better see the differences instead of just switching them. Anyway, keep up the good work.

[@thephotographytoolkit]

Thanks Kashii. I appreciate the comment and recommendation.

[@paulrajmichael2320]

Your explaination is very details and clear. Thank you so much for sharing your knowledge Dave Caleb.

[@thephotographytoolkit]

Thanks so much Paul!

[@rdn658]

As a beginner, this is very informative. Now, I will consider the aperture using the APS-C sensor.

[@thephotographytoolkit]

I am glad it was useful. Thanks for sharing!

[@sarathchandran570]

Wow, superb explanation which never seen before. 👏🏻👏🏻 Great info, thanks a bunch ❤

[@thephotographytoolkit]

Thanks so much for the very kind comment.

[@GreySectoid]

Great video! If I got a cent every time someone gets this wrong on youtube I'd be able to afford a Leica.

[@thephotographytoolkit]

Thanks so much Terry. I enjoyed testing out the photos myself and seeing the results.

[@selah2911]

Thank you!!! I finally understand this! I’ve bought 2 FF lenses thinking I’d eventually upgrade to FF from crop sensor. But I really stuggle feeling satisfied with my current work because often I’m not achieving that buttery (1.4-2.8ish) background that I desire. I may just want to get a crop sensor lens after all to achieve it OR it’s just time to get a full frame body! Thank you, best explanation ever.

[@thephotographytoolkit]

Thanks so much for your comment Selah. I am really glad that it helped you understand lenses with FF and APSC/crop sensors. The other great thing about a FF camera is when you are using the same lens, you need to be closer to your subject to get the same framing as when using the same lens on an APSC/crop sensor camera. The closer you are, the blurrier the background.

[@gregh988]

This is an incredible video. You anticipated every question I had and everything comparison I wanted to see, thanks a ton.

[@thephotographytoolkit]

Thanks so much Greg. I really appreciate your comment.

[@paul.newland]

Outstanding explanation - best on YT! 👍 Sadly, some folks will still put their head in the sand and argue because they don’t come from the pre-digital era and don’t have the 24 x 36mm film frame understanding as their reference base…

[@thephotographytoolkit]

Thanks so much Paul! I do get surprised with some of the angrier people out there. When I started to look into this, I honestly didn't know what the results would be. It was such a great experience to test and learn.

[@Meothui22]

The best explanation on YT about how aps-c affects bokeh. Thank you.

[@thephotographytoolkit]

Thank you so much for your kind words! I really appreciate it.

[@ant_clem]

Great video with very good examples! However, I would like to add to it by talking about pixel density. I agree that the image projected by the lens is the same and that the image received by the APS-C sensor is a crop of the image received by a FX sensor, but if you were to use a D500 with a 20.9MP APS-C sensor and a D750 with a 24.3MP FX sensor and crop to get the same size image as the APS-C, the image produced by de D500 APS-C sensor would have a lot higher resolution. If you divid the MP count of each sensor by it's area, you get a pixel density of 0.0544 MP/mm2 for the 20.9MP APS-C sensor and a pixel density of 0.0281 MP/mm2 for the 24.3MP FX sensor. If you multiply the pixel density of the FX sensor by the area of the APS-C sensor you get a 10.8 MP image, which is, in my opinion, quite a big deal in certain situation. You have the chance to own a D850, a FX camera with a 45.4 MP sensor (which would still as a smaller pixel density than the D500 sensor but barely noticeable), so the difference is a lot less apparent, but most people who want to try a FX camera for the first time probably won't have access to such a camera. I understand that the point of the video wasn't really about that, but I find that most video discussing the two format often don't talk about that aspect or explains it very poorly. Again, thank you for the time you took making this video!

[@thephotographytoolkit]

Thanks so much for your insight into pixel density Antoine! That is a really good point that if you have a FX sensor it may have a lower pixel density than an APS-C sized sensor even if they have similar number of megapixels. The big idea I wanted to make was that the you can't just multiply the lens focal length by 1.5 when you use that lens on an APS-C sized sensor. The image will not look the same as the equivalent focal length of an FX sensor. Maybe a pixel density video is one that I could make in the future. Thanks again for your comment!

[@cherylwilcox9648]

Awesome explanation - thank you!

[@thephotographytoolkit]

I'm glad it was useful!

[@saramulry]

THANK YOU!! Man I’m so glad I found your video, this has been confounding me for so long 😅

[@thephotographytoolkit]

I am really glad it was helpful!

[@ricban1950]

Thank you for the aperture details. It's been screwing my head since I started with 4/3ds 14 years ago. I now understand how to apply your explanation to the 5 Olympus Zuiko legacy lenses I still have.

[@thephotographytoolkit]

Happy to help!

[@christianmani1730]

Wow, the best explanation of this topic I've seen yet.

[@thephotographytoolkit]

Thanks so much Christian. Your comment made my day.

[@DucNguyen-cq5iw]

The video was very informative and easy to understand. I appreciate the effort you put into making such a clear and concise explanation

[@thephotographytoolkit]

Thanks so much Duc. I am glad that it is clear. I did enjoy capturing and comparing the images that really helped to illustrate the idea that I was trying to explain.

[@ppBizU]

yeap, you're right. It was quite annoying when big channels say it's not a different, it's different.

[@thephotographytoolkit]

Thanks so much for your comment and support.

[@okaro6595]

2:20 there is more blur on the full frame lens as the aperture is bigger. The other differences are because some optical differences in the lens design like where the optical center of the lens is and are because the subject is so close. Generally there is a principle that cropping produces same results as increasing the focal length if issue like image quality and background blur are ignored. Te f stands for focal length. It is written as for example f/2 because the aperture size is the focal length divided by two.

[@thephotographytoolkit]

Thanks so much for your comment Okaro. I totally understand that when the lens is zoomed the elements move and the optical center of the lens changes. A number of people who I have spoken with believe that a lens (ex. 14mm) on an APSC sensor camera will give you the same look as the equivalent focal length (ex. 21mm) on a full frame camera. So I wanted to show the differences.

[@bala1000mina]

Thank you so much David for the awesome explanation of math behind the using lenses on crop sensor cameras! Very helpful and informative for me. God bless you and good luck!

[@thephotographytoolkit]

Thank you so much for the comment Nate! I am really happy that all the work put into the video is helpful.

[@Mandelrot]

Whao, I've learnt a lot with this explanation and now many things make more sense. Thank you very much.

[@thephotographytoolkit]

I am really happy that it was helpful. Thanks so much for the kind words.

[@learningCountry]

Best explanation on crop vs full frame. Thank you!

[@thephotographytoolkit]

Thanks so much.

[@KidRichmond]

Finally a clear explanation with demonstration.

[@thephotographytoolkit]

Thanks so much! I really appreciate it.

[@mackenlyparmelee5440]

This has very interesting implications for medium and large format photography. Thank you, I'm glad I watched your video!

[@thephotographytoolkit]

Thanks so much for the comment. I totally agree. Most people talk about equivalence when it comes to full frame vs APSC but it gets really interesting with medium format. For example, I have Fujifilm GFX 50R and it has a 100mm F2 lens. You need to reduce the focal length and aperture to get the equivalence for a full frame camera. So that 110mm f2 lens has an equivalent focal length of 87mm and equivalent aperture of f1.7 when compared to full frame. You can see more here: shuttermuse.com/fujifilm-gfx-crop-factor-and-gf-lens-35mm-full-frame-equivalent-focal-lengths/

[@mackenlyparmelee5440]

​@@thephotographytoolkit Awesome article! Yes you could think of 35mm as a crop of larger formats too. the same rules apply. My subject shot at a given focal length will objectively look the same size on every format. All I'm doing by changing the focal length is making the subject larger or smaller relative to the total size of the negative. Same thing with the DOF. If I just made the image circle of a 35mm camera lens larger and projected it onto a larger negative, then shrunk that down to the size of the 35mm negative, it would like like I was shooting larger aperture and from farther away. It's all clear now, thank you again!

[@thephotographytoolkit]

@@mackenlyparmelee5440 Happy to help! Thanks so much for your comment and for sharing.

[@simonpayne7994]

F does not mean fraction! "f" means focal length. The correct designation is e.g. f/2.8 and not F 2.8. In other words, an aperture stop is defined by the ratio of the focal length to the number in the denominator. An aperture stop at f/2 for an f = 50 mm lens means that the (effective) diameter of the aperture is set to half the focal length, i.e. 25 mm. For a very simply built lens, consisting of a single chunk of glass, with a sensational maximum aperture of f/1.0 the whole contraption would be just as wide as it is long. Actually slightly wider than the length because the sensor is usually not at the very front of the camera.

[@gerhardbotha7336]

Great contribution. If there is one thing I don’t understand it is a DOF calculator. It asks for the focal length, the F stop, the distance to the subject, and the sensor size. It gives the DOF in inches or cm. If I put a lens on a FF body and take a shot, and then repeat with. a CF, the result is as shown in your clip. The image is identical, the CF is just a crop of the FF. yet, the DOF calculator will tell you the DOF is different. What is going on there?

[@thephotographytoolkit]

Thanks for the question Gerhard. Honestly, I haven't ever used a DOF calculator. When I looked one up, the first one that google gave me was photopills (www.photopills.com/calculators/dof). My first question is when I select a focal length for a APSC sensor camera and then select a focal length, is that focal length for a full frame (FX) or is it a APSC lens (DX)?

[@gabedamien]

Your first comparison is invalidated somewhat for several reasons: - The actual crop factor of Nikon is 1.53, not 1.5. So 14mm on DX you would need 21.4mm on FX to achieve an identical look (identical field of view + identical perspective, resulting in identical relative sizes of foreground and background). Or for 21mm on FX you would need 39.6mm on DX. Now, granted, that is a small difference, which brings me to my much bigger point: - Focus breathing! When focusing close, lenses don't necessarily result in their marked or recorded focal length. Many lenses when they shift their elements to optimize for close focus exhibit focus breathing, where the actual focal length changes from its nominal focal length. So your test doesn't necessarily show an accurate portrayal of either 14mm or 21mm rendering! And despite using the same zoom lens model to achieve both, the potential error with focus breathing is not identical throughout the zoom range, so you could have a larger error at one end of the range than the other. The only fair way to do this comparison, in fact, is to either optically measure the true focal distance at each zoom setting and focus setting, or (more practically) to perform the test at infinity focus, which is the only focus setting at which your zoom lens markings and metadata are accurately spec'd. That does however make your other points about relative background blur size harder to demonstrate, so the best compromise is to use a lens that is known to exhibit near-zero focus breathing. - By a similar token, even though you are using the same camera and same lens on a tripod, you may be surprised to discover that when you changed the zoom setting, your physical perspective actually changed too: because when the lens elements moved to achieve the zoom, the optical center of the lens moved as well, and THAT is what defines the perspective (not the focal plane). This error is again quite small, but it is big enough that when we do stitched panoramas we have to center a lens over its optical center and NOT the focal plane, otherwise we get perspective mismatches where foreground and background elements do not overlap consistently between panorama shots. This error is again compounded more noticeably at closer focusing distances. It can be corrected for the same way we correct for it in stitched panos: by using a slider or long lens foot, plus panning, to find the optical center, thus achieving identical perspective for each zoom setting. You are strictly correct that the physical focal length of a lens does not change just because we put a different sensor behind it. You are technically incorrect however in your assertion that the equivalent focal lengths for each sensor size will "look different". They only look different here because we haven't actually held all other variables constant: we don't know the true focal lengths for this lens at this focus distance, the optical center of the lens has moved during the zoom, and the precisely correct nominal focal lengths weren't set in the first place. If you could magically set up a test where all other variables were actually held constant, then the test would demonstrate the point that equivalent focal lengths actually do result in identical rendering. I have done this myself with certain lens pairs, while others seem to fail as you demonstrate. This is due not to problems with theory, but due to practical effects like a shifting optical center which muddy the waters, requiring a lot more care to keep the test fair.

[@thephotographytoolkit]

Thanks for your thoughts.

[@deardaughter]

This is the best video ever made on KZbin

[@thephotographytoolkit]

Thanks so much for the wonderful comment! I'm happy that all the hard work I put into the video was worth it.

[@royalweddingfilmsuk]

best explanation online! Thank you.

[@thephotographytoolkit]

Thank you SO much! I really appreciate the positive feedback!

[@christopherward5065]

Spot on. However in real use terms the grammar of the shots being taken will be dictated by the camera. The photographer will be aiming to produce a particular feel in an image with the camera and lens in use. The need to do a mathematical equivalence conversion is not how we work in reality. Someone working between two formats is aware of what works in each format and how to create the image in each format. An APSC photographer will still choose their lenses for the effect that they produce and a 300mm full frame lens will produce the same field of view as a 300mm APSC lens if both are being used on the same APSC body. That photographer will be aware of what that looks like and it’s fine to use either lens. The photographer won’t be using it as a 450mm lens. I think the confusion comes from the idea that you have to know the equivalent, you don’t. Just use the lenses that work for the shot in the format you are in for the effect that you need.

[@thephotographytoolkit]

Really well said Christopher. Totally agree with you. And that is why I own and use both full frame sensor cameras and APSC sensor cameras. Thanks for your insightful comment.

[@marvectv]

This is the best explanation On this topic. Thanks a million ❤

[@thephotographytoolkit]

Thanks so much Martins! Glad it was helpful!

[@dianacotovan8642]

Really well explained! I found your video because recently I was hyped for trying some of my lenses on a crop sensor but then I realised that, as you said, the images you get are exactly that - cropped - and not results of extended lens capabilities. The way I explained it to myself is that you cannot extend the physical characteristics (the optics/optical limits) of a lens simply by changing to a cropped (that is, a limited) sensor camera. There are physical limits to a lens and a (limited/cropped) sensor cannot change the properties of a lens, therefore it only made sense that what you get on your memory card is just a fragment of the same image taken with a full sensor. However, taking advantage of the equivalent focal length does spare me from having to buy a TS 24mm, at least for the time being :D (still need to test this, though - and I pray it's not going to be completely useless :D ) P.S. Great info about the aperture, and the "equivalent" focal length.

[@thephotographytoolkit]

Thanks so much Diana. I like the way you explained it. You are right, the properties of the lens don't change. What are your plans for the TS 24mm? I have 19mm PC Nikon lens but I haven't tried it on a crop sensor camera.

[@dianacotovan8642]

@@thephotographytoolkit hey, you’re welcome, David! What I’m trying to achieve with a 17 mm TS lens (1.6 crop factor takes it to 27mm, so slightly above 24mm which is the next in line for Canon TS lenses, afaik) on a crop sensor is to get rid of the wide field of view you get with a 17mm, and by shifting the lens to be able to focus on certain parts of an interior or a building (either in a single shot, or even by stitching a few shots without getting the full width of the lens that you get with a full frame camera, if that makes sense). I like to shoot architecture and interiors, hence my idea for this experiment.

[@thephotographytoolkit]

@@dianacotovan8642 Ahhhh, I see. That does make sense. The 17mm TS is a beautiful lens. The 1.6 crop factor for Canon is great for telephotos but more painful on the wide angle lenses. I would be interested to see how the stitching works out for you. Good luck with your shots!

[@dianacotovan8642]

@@thephotographytoolkit Let's see how it goes. Thank you! 😅

[@RedDonasco]

superb explanation! thank you!

[@thephotographytoolkit]

You are more than welcome. I am glad it was helpful.

[@scottlatimer7912]

This video was uniquely informative, and I have noticed similar background blur effects. I purchased the OM 4/3 system for a trip to Africa because it minimizes weight and provides superior focal length gain. Now, you tell me I could just use a full-frame camera and crop the image? The only downside I see is the accuracy of focus. With the crop sensor, I was able to generate very sharp images with the OM camera and lenses because of the field-magnified vision of the animals thanks to the crop sensor magnification effect. Not sure I would get the same focus accuracy with a full frame that was later cropped. Thoughts?

[@thephotographytoolkit]

That is a fair point Scott. I haven't tested focus accuracy with a smaller sensor compared to a bigger sensor. I am wondering if that has more to do with the camera's focusing system and if we could even make a fair test. If you have 2 different cameras with different sensor sizes and focusing systems, there may be too many different factors to do a test. I am also wondering if while focusing with a larger sensor, I could just zoom in and then focus and if that would make my focusing any more accurate. Thanks for the comment and question.

[@puppylover278]

but how do you get zooms with a constant aperture? the vocal length changes but not the opening?

[@thephotographytoolkit]

That is a really great question! When you zoom a lens with a constant aperture, the size of the aperture changes as you zoom. So when zooming a 70-200mm f2.8 lens starting at 70mm and zooming to 200mm you can see the aperture inside the lens getting bigger as you zoom.

[@shivashrestha1061]

Great explanation, helped me a lot. One question tho: As you mentioned FF F4 “looks” like F6 on APSC . Does it also mean decrease in lowlight capturing capacity on Cropped sensor?

[@thephotographytoolkit]

Great question Shiva. The lowlight capacity is no different on a full frame sensor or a cropped sensor. The amount of light coming through the lens is the same. It is just that the 'equivalent aperture' is different. That means F4 on FF will look like F6 on APSC.

[@shivashrestha1061]

@@thephotographytoolkit thanks a lot 🙏 😊

[@thephotographytoolkit]

@@shivashrestha1061 Happy to help Shiva.

[@CanalVitorSilvaGTR]

Great video. The big point I think creates confusion is when you say that an FF F4 lens on a crop sensor produces an equivalent F6 aperture, because this is related to the equivalent depth of field, not the amount of light that the crop sensor is getting. The FF lenses have larger glasses to cover the FF sensor and, consequently, in a crop sensor, they end up transmitting more light. This is clear in your photos, which have not gotten darker with the crop sensor. Quite the contrary, if you observe at 9:08 time, the background of the image with crop sensor is clearer than the background of the image with FF sensor, precisely because the sensor is getting more light than if it were with an APS lens. This ends up being an interesting property of using FF lenses on crop sensors.

[@CanalVitorSilvaGTR]

At the end of the video (10:29), it becomes even clearer by adjusting the equivalent depth of field on the FF sensor, when the crop sensor image is brighter... that is, the crop sensor reaches the same depth of field, however, with a more illuminated image. That's why people consider that the aperture does not change, because they consider the amount of light, not the depth of field as a parameter. If on the same crop sensor we use an FF 70mm F4 lens and a APS 70mm F4 lens, the first will have a more brightness image, because it allows more light, however, with a higher depth of field.

[@thephotographytoolkit]

Thanks so much for the comment and for the explanation. You're right that when I say that the equivalent aperture of a FF lens on a crop sensor camera is related to depth of field and not the amount of light.

[@okaro6595]

The problem is that you did not take into consideration the equivalent ISO. The equivalent ISO is higher as the equivalent aperture would need higher ISO.

[@OhhhhhhhBugger]

Only thing you really need to know these days is that a crop camera is really the best for macro, astro, and telephoto wildlife photography that doesn't have ultra low light needs. FF does do well in low light, but doesn't have crop factor. To me, crop factor is a benefit, a feature, that I use tremendously to my advantage. Modern cropped cameras do not suffer the same noise issues of days past, so the only limiting factors are really whether you want a bigger or smaller image circle. And yes, cropped cameras do bring changes to depth of field, but most lenses can be adjusted accordingly. I almost never shoot macro at F2.8 or wildlife at F4 anyways. The better DOF actually benefits you in wildlife shots and macro too.

[@thephotographytoolkit]

Thanks for the comment. I totally agree with everything you are saying. I am definitely not saying that full frame cameras are better than APSC/crop sensor cameras. I own both and use both. I use my crop sensor cameras for wildlife and sports all the time. The whole point of the video isn't which sensor size it better. The point is that people often think that if they have a 60mm lens on an APSC/crop sensor camera, that it will look the same as a 90mm lens on a full frame camera and it won't. That is all. Thanks again for your contribution.

[@bruhitsme2601]

So much confusion, thanks for the explanation.

[@thephotographytoolkit]

Glad it was helpful!

[@teacherofteachers1239]

I'm only two minutes in and my mind is officially blown. Terrific, clear demonstrations and explanations.

[@thephotographytoolkit]

Thank you so much for your wonderful comment. I really enjoyed capturing the images that actually showed the difference. The first time I did it I was surprised and blown away by the difference in background blur.

[@GeneralKiller1337]

This explanation is so clear. Congratulations

[@thephotographytoolkit]

Thanks so much for the kind comment.

[@kadevent]

well explained

[@thephotographytoolkit]

Thanks so much!

[@tjburkecreative]

Super informative, been contemplating better glass for now and then getting going full frame later. One question, is the focus point the in the same place on the Buddha? It seems that it shifted from the left eye to the right eye between FX and DX. Just wondering if that could have made a difference with focus breathing? Regardless, great video. Thanks for putting this together!

[@thephotographytoolkit]

Thanks for the comment TJ. When I did the comparison, I turned everything to manual including the focus so it shouldn't have changed at all. Where exactly in the video are you seeing the shift? Thanks!

[@CakeorDeath420]

This is well explained with good examples. A very confusing subject for many around which lots of discussion are had. Great video. You should have more subscribers.

[@thephotographytoolkit]

Thank you so much for the kind and encouraging words!

[@AzarathGirl123]

Wish i had seen this video when i first got into photography, i was very confused back then tho i did figure out on my own after a lot of thinking 😅

[@thephotographytoolkit]

Thanks so much for the nice comment Raven. I am glad it is helpful.

[@zetacrucis681]

f stands for _focal lenth_ not _fraction_ for reasons you actually explained: Aperture = Focal length / f-number = f/f_number

[@thephotographytoolkit]

Thanks for the clarification!

[@dalefrolander3583]

I only count the equivalent fov. For example, the 200mm f4 lens on a crop sensor camera has the equivalent fov of 300mm and the depth of field of 200mm at f4. No reason to convert the aperture as it is exactly 200mm at f4.

[@thephotographytoolkit]

I understand that a 200mm lens has an equivalent fov of a 300mm lens but I think it is confusing to say that it has an equivalent depth of field of a 200mm lens at f4. It is true but not easy to visualize. The picture from an APSC camera with a 200mm f4 lens will look like a 300mm lens set to f6 on a full frame camera. Thanks for the comment.

[@robackerman4466]

Brilliant explanation. Well done and thank you!

[@thephotographytoolkit]

Thanks so much! I really appreciate it.

[@madandoyajle7542]

Wow sir , Very nice sir, you have explained very well. Thank you

[@thephotographytoolkit]

Thanks so much for the kind comment. I am glad that you liked the video.

[@szalacsisandor2841]

Put the same lens on a crop, then a FF camera. Set same ISO and aperture on both. Take a picture with both, with similar framing. Shutter speeds will be the same on both cameras. Aperture and exposure doesnt change.

[@thephotographytoolkit]

You are correct. The aperture and shutter speeds for my shots were exactly the same. But the resulting photos looked different on an APSC crop sensor and a full frame sensor. Thanks for your comment.

[@cindyblacklock9764]

Best explanation I've seen yet - I finally get it!

[@thephotographytoolkit]

Thanks so much Cindy! I worked a lot on it to try to make it understandable with examples. I am glad it helps.

[@wv5959]

Well explained! 👏🏼 What was missing is a short explanation if light / exposure is affected or not.

[@thephotographytoolkit]

Thanks so much. For these examples the exposure was the same.

[@DrunKid]

​@@thephotographytoolkitwas the ISO static in all of the pictures? In other words, the only part that is affected by the aperture is the bokeh, not the brightness?

[@thephotographytoolkit]

@@DrunKid Thanks for the question. Yes - the ISO was the same for every single image.

[@davidliu323]

My mind is blown. I didn’t know the background compression could change depending on the focal length. I always thought changing focal length was nothing more than essentially an optical crop. Thanks for making this video!

[@thephotographytoolkit]

Thanks so much for the comment. I'm really happy that all the work that I put into the video is helpful.

[@RudolfWolph]

It can be demonstrated that two lenses with the same focal length used on the same format don't always have the same distortion characteristics, so can I claim when someone else's 24mm lens doesn't match mine that theirs "doesn't have the characteristics of a 24mm lens"? This is the same sort of reasoning that led people to believe medium format is somehow less distorted than full frame or aps-c because the lenses have to be longer focal lengths for any given AoV/FoV It's simply not true. (Btw, the center of perspective of a lens is the entrance pupil. Keeping the camera in the same position when you change lenses will not keep your perspective consistent between lenses.)

[@vincentli2090]

I believe that's the no parallax point, or some call it the nodal point.

[@thephotographytoolkit]

I totally understand that different lenses with the same focal length can have difference characteristics. I have actually been experimenting with that exact idea with three 50mm F1.4 lenses that I have (Nikon D, Nikon G, and Carl Zeiss). With those lenses it was more about differences in the bokeh as there were no distortion differences.

[@DrunKid]

Thank you so much for this! Question; do I need to take these things into consideration if I opt for an ASPC lens? In other words, is f2.8 on a crop lens still equivalent to 4.2 on a full frame?

[@thephotographytoolkit]

Thanks for the question about APS-C lenses. You are correct - an f2.8 lens will have an equivalent aperture of f4.2 on a full frame camera.

[@moodkhosh-ik7ux]

Thanks, very good and informative video

[@thephotographytoolkit]

Thanks so much.

[@christopherberry8519]

Yeah - small mess-up. F stands for focal length - not fraction - but you were close... Aperture is f/4 - in other words the focal length divided by 4. 100mm f/4 = 25mm. 200mm f/8 is also 25mm... - Same aperture, different f/ number. As a proportion of 2 measurements, it has no units.

[@thephotographytoolkit]

Thanks for the information Christopher. I appreciate it.

[@ChrisThe1]

Excellent explanation of how crop affects aperture. Really great. But, equivalent focal lengths are the exact same; they don't have different perspective.

[@thephotographytoolkit]

Thanks so much Chris. Can you tell me more about what you are saying? I am not sure if I am understanding you. I captured the images from the exact same perspective with a APSC (cropped) sensor and a (35mm) full frame sensor. When it comes to equivalent focal length's I find this video is also really helpful: kzbin.info/www/bejne/sJ7PnpuojbuZm7csi=EeYcDBSupY7KK7fr&t=64 Thanks!

[@ChrisThe1]

@@thephotographytoolkit that‘s a good video, but it supports my point. in your experiment there are too many factors at play. lenses have different focal lengths than they say, those change even more at close distance. also, if you mounted the cameras on the same tripod the sensor will be placed slightly differently in the camera. all of these factors will be exaggerated by the really wide angle of view you‘ve chosen. if you think about it you can‘t achieve a different perspective without moving the camera location, so focal length or sensor size doesn‘t change the perspective, they just change the crop of the image

[@thephotographytoolkit]

@@ChrisThe1 I guess we will have to agree to disagree Chris. In my examples, I limited the factors that changed to exactly one thing: the focal length of the lens..I purposefully used a zoom lens so it would have the same lens elements. I know the lens elements move inside the lens when zooming, but there isn't anything I can do about that. Nothing else changed or moved.

[@ChrisThe1]

@@thephotographytoolkit distortion changes as you zoom. Also with the wide aperture and different set focus distance it's hard to compare.

[@thephotographytoolkit]

@@ChrisThe1 Like I said Chris, we are just going to have to agree to disagree. The purpose of my video is to show that you can't just multiply the focal length of a full frame lens when you put it on a APSC camera and get the same image as you would on a full frame sensor. A 14mm FF lens on an APSC camera will look different than a 21mm lens on a FF camera. If you are still not convinced, I would recommend doing the test yourself.

[@silas1414]

Beautify explained and demonstrated.

[@thephotographytoolkit]

Thanks so much Silas!

[@RiyadhKey]

Very well done, but the point of Aperture is confusing, what about a Zoom lens, say 70-200 f2.8, is the Aperture different when its 70mm vs 200mm? it is known the larger the FL, the shallower thr DoF, but light is the same.

[@thephotographytoolkit]

Thanks - that is a really great question! With a zoom lens like a 70-200mm F2.8, the size of the opening of the aperture actually gets larger as you zoom from 70mm to 200mm. It is easy to see in an older 70-200mm which has an aperture ring because you can just set the aperture to F2.8 and zoom the lens from 70mm to 200mm and you will see the size of the aperture opening increase as you zoom to longer focal lengths. It is also possible to do this with a newer lens without an aperture ring by putting it on the camera and setting the aperture to F2.8 and then taking it off the camera without turning off the camera first. If you don't turn off the camera, the aperture will stay at F2.8 when the lens comes off the camera and you will be able to see when you look through the lens and zoom that the aperture opening actually increases. I might be able to make a video to show this if that is helpful.

[@okaro6595]

The lens has constant aperture so it gathers same amount of light fully open at any focal length. When you zoom in it gathers light from a narrower angle so it would get less light but for that reason the size of the aperture (not the aperture value) is larger at 200 mm. It is 200 mm / 2.8 = 71 mm when at 70 mm it is 70 mm / 2.8 = 25 mm. At 20 mm you of course get more blur. Note even on variable aperture zoom the aperture is larger at the tele end like typical 18-55 mm f/3.5-5.6 kit lens. At 18 mm it is 5 mm and at 55 mm 10 mm.

[@coachgaryang]

Thank you so much for this video!! It helped me a lot! Been looking at forums and i couldn't understand by reading. Your explanation is awesome!! Quick question, with the difference in aperture and bokeh effect, does it mean the amount of lights let in is much lesser as well while using a FF lense on a apsc camera?

[@thephotographytoolkit]

I am glad that the video helped you Gary! The amount of light is exactly the same as the size of the aperture is the same. The reason the bokeh effect is different when the cameras are in the same spot is because of the focal length is different. I hope that helps.

[@coachgaryang]

@@thephotographytoolkit THANK YOU SO MUCH! I LOVE YOUUUU

[@thephotographytoolkit]

@@coachgaryang Happy to help Gary.

[@sergeykovalev1195]

The most useful video I saw today

[@thephotographytoolkit]

Thanks so much! I am glad it was useful.

[@igormelo2057]

I really regret buying a Canon R7, such an amazing camera, but the APSC sensor gets me frustrated

[@thephotographytoolkit]

I totally understand. I enjoy my APSC sensors for what they are and I mostly use them for wildlife and sports.

[@okaro6595]

Characteristics of the lens? What does that mean? Flare, imperfections etc. yeas. Note when you shoot so close you may get strange results as the optical center does not remain at exactly the same position. Also those could be explained by barrel distortion. You should do it again with normal shooting distances.

[@thephotographytoolkit]

Thanks for the comment Okaro. Yes - characteristics of the lens means that different lenses can look different - even lenses of the same focal length. If I had done this test and used two different lenses, I would have gotten lots of comments that I can't compare two different lenses because there are differences between those lenses and they affect the results. Does that make sense? When I am close the look of the statue will look different than when I am further away. I made sure that the camera was secure so that nothing would move so that everything would be as fair as possible. The fact is that when I am close to my subject with a 14mm focal length on a full frame camera I will get a certain look and I will get a different look with a 21mm lens on an APSC camera from the same spot. You mention that I should try it again with normal shooting distances. What do you mean by normal? Not close to my subject? In another part of the video I use a telephoto lens and there are still differences: kzbin.info/www/bejne/pF7ag2R8n7yLidUsi=t2rQ5sGbMqZmFots&t=500 I didn't just use a wide angle lens, I used a telephoto lens and there were also differences. Thanks again for your comments.

[@antonroland]

What is a normal shooting distance?

[@thephotographytoolkit]

@@antonroland Great question. There is no such thing.

[@chuyencuaco]

Very nice, I watch many videos about this subject, but your video is explain with pictures every informative and easy to understand!

[@thephotographytoolkit]

Thanks so much for the comment! I really appreciate it and I am glad it was easy to understand. Nhân tiện, tôi đã sống ở Việt Nam được 6 năm. Bây giờ tôi sống ở Singapore.

[@wayoflifebydrayush1399]

Great what have you explained..I could not find any video explaining this fact. You cleared my many doubts.

[@thephotographytoolkit]

Thanks so much! I am really happy it was helpful.

[@danielmorgadez684]

I'm going into wildlife photography as a hobby is going crop or full frame a huge concern?

[@thephotographytoolkit]

If you are going to capture wildlife images, I like the 1.5x crop APSC camera. That being said, I do like a full frame camera with a larger sensor if it is darker.

[@johnwinter6061]

Whether you use FF or APS-C just get a zoom lens! With a zoom lens you can replicate a wide range of typical FF v APS-C fixed lens outcomes just by using the zoom and changing where you stand, regardless of whether you are using FF or APS-C. Regardless of effective / actual f/stop, lens focal length, etc, it's the outcome we want to get. No-one has ever said to me, "Oh, you took that with a zoom lens." Never. Oh I hear you saying. 1. Loss of IQ. Maybe. I've been using zooms since 35mm film days in the 1980s. They've improved a lot since then. 2. Zooms don't usually come in F1.4 so can't get good bokeh. In many cases, you can even with a F5.6 zoom lens. Step back and use a longer focal length. You can also fix some background issues in software. 3. Auto focusing issues. Maybe in rare low light. 4. Can't see enough in the viewfinder. Never a problem on my DSLR with mirror. Irrelevant on my mirrorless. FF sensors v APS-C sensors? The gap is closing. As APS-C quality improves, the prices for each are getting closer to each other. So that choice may not be that relevant in the future. What will be relevant is that it costs less to make an APS-C only lens. Mirrorless has also reduced costs. Decades ago 35mm film brough us cheaper and better lenses versus the larger format 620/120 roll film. I've backed both! RP (FF) + 24-240 and an R50 (APS-C) + 100-400. I have an 'effective' range of 24-636mm and an overlap from 160mm - 240mm. Beauty is 1. Both those are FF lenses so I can interchange. 2. I'm not fiddling around with changing lenses in hostile environments. Those two zooms are FF yet competitively priced against APS-C only lenses. IQ is quite good.

[@thephotographytoolkit]

Thanks for the comment John. I think that some people think that I am trying to say that I don't like APSC or that full frame is better and that couldn't be further from the truth. I own and love APSC cameras. I also think it is great that you had this internal dialogue about what I would say. And you assumed I would disparage zooms or think zooms are inferior. I love zoom lenses! I own a ton of them and use them every day. I agree that no one has ever said to me that I captured an image with a zoom lens. I have talked with a number of people who say that their 70-200mm f2.8 lens full frame lens is a 105-300mm f2.8 lens. So I did a lot of research and tests and I am just sharing what I have found out in these tests and what I have learned. No harmful or malicious intentions towards any sensor size or zoom lens. I promise. The point of my video is that you can't just multiply the focal length of a full frame lens when you put it on a APSC camera and you will get the same image as you would on a full frame sensor. A 14mm FF lens on a APSC camera will look different than a 21mm lens on a FF camera. That is all.

[@johnwinter6061]

@@thephotographytoolkit I made no assumptions at all. None. My comment (six hours ago as I type) was for the broader audience. My comment re FF was about the use of the name FF and not comparing the merits of different formats. The debate of FF V APS-C was clear about 10 years ago. That's now changed. The lines are now very blurry. In many cases it's horses for courses. ie Pick the format and lens according to the subject matter you usually shoot and your budget. Whilst a 14mm FF on an APS-C may not be the same identical image as 21mm (or 22.4mm for Canon) on FF, it is possible to make very close matching images by changing standing position, focal length and f/stop. Other videos have shown examples. A zoom lens simply makes this easier to do. Others are debating on other web pages about whether to use FF lens on APS-C. Once again it is possible to get very close matches of images with both FF lenses and APS-C lenses on APS-C. Again zoom lenses make this easier to do. The bottom line is simple. Have you got what you want? If not, instead of following the blind mantra about what equipment you need to buy, consider equivalents in what you have. Again much easier with zooms. No need for maths. Just look at the image. Is that what you want? If not, change something - where you are standing, focal length & f-stop. The effect of ISO and shutter speed can be considered separately. Extension rings are also another cheap variable. You may not need a fast lens for good bokeh. Might be/seem easier. But what you have may be able to do something similar. Especially if you consider your background before taking the shot!

[@thephotographytoolkit]

@@johnwinter6061 Thanks for the clarification John.

[@ZommBleed]

Literally the ONLY one on KZbin who can technically explain this. Also, the only one who has the correct explanation of the "f/" in a stop value. You win the internet, Sir.

[@thephotographytoolkit]

Thank you so much! You totally made my day! I am glad that all the work I put into the video is helpful. I'll definitely take that win!

[@MobiusCoin]

I'm actually shocked that this has to be explained in this detail. I never confused equivalent FOV with the actual focal length. I think this confusion only arises when you learn the effect of focal length rather than what focal length actually is. Learning a little bit about optics goes a long way. Now I'm wondering if people don't actually know the causal mechanisms of photography now. Like do people understand why chromatic abberation is more pronounced when the lens is wide open?

[@thephotographytoolkit]

There are so many levels of understanding and there is no shame in knowing or not something. We are all at different stages in our learning journey when it comes to photography. I love learning and I love sharing. I would love to learn from you about why chromatic aberration is more pronounced when the lens is wide open. Thanks for the comment.

[@StrangelyIronic]

Isn't it common sense that, even if you apply crop factor to a given focal length, you're still working with the original focal length, just "zoomed" in? MFT users know that even if our 25mm lens gives an effective fov of 50mm, optically you're working with a wide angle 25mm. That's one way you can achieve different levels of compassion with effective fovs. Also while you have, say, f/4 instead of f/2 in terms of depth of field, you're still getting f/2 worth of light on the sensor, crop doesn't apply to that. There's also other aspects that control depth of field just like exposure is a combination of elements. The only misconceptions are from people mindlessly part of the "full frame or nothing" club that spend most of their time talking about cameras rather than shooting them.

[@thephotographytoolkit]

Thanks for the comment. I agree with you that it is common sense that when one applies a crop factor to a given focal length, it is just 'zoomed' in. However, what many people do have misconceptions about is that a the look of the image captured on a APSC size sensor will be the same as a longer focal length lens on a full frame sensor. For example, a 14mm lens on an APSC sensor camera will have a different look than a 21mm lens on a full frame sensor camera even though they have equivalent focal lengths and are captured from exactly the same spot. kzbin.info/www/bejne/pF7ag2R8n7yLidU And that is what I was demonstrating - the exact difference of the look when comparing different (but equivalent) focal lengths when used on different sensor sizes. I honestly just love cameras and although I don’t own a MFT camera, I have used one. I currently own and use cameras with APSC sensors, full frame sensors and medium format sensors. So can you tell me more about your “full frame or nothing” comment?

[@okaro6595]

No, 25 mm is not wide angle on MFT. It is the normal. I think you meant compression and not compassion. Lets say simply: you are totally wrong. You have invented some new laws of optics where there is some compression dependent on the sensor size. This nonsense is common on medium format shooters and if has been totally debunked. You get f/2 worth of light which allow you to have lower ISO but as the sensor is smaller you have to have lower ISO for the same noise level. Smaller sensor offers no free lunch. Full frame can always simulate smaller sensor by stopping down and raising the ISO. Same cannot necessarily be done with smaller sensor as there might not be large enough aperture or low enough ISO. The claim that full frame users do not shoot their cameras was a cheap shot.

[@joeguetzloff4465]

If I put my Sigma 150-600 Contemporary lens on my FF Canon 24MP camera then switch bodies to my old APS-C 24MP camera, I get a "closer" image with the same amount of megapixels. At 3:10 you said that if you crop the FF image to look like the crop sensor image, the results are identical. Not true. You now have less than 6000x4000 pixels in the FF image that you cropped in a program. Meaning less resolution. Meanwhile, the crop sensor image is still 6000x4000 pixels. 😉

[@thephotographytoolkit]

Fair comment Joe. If both the cameras are the same number of megapixels, then your APSC size image will get a "closer" image with the same amount of MP. And that is the advantage of the APSC format and why I have APSC cameras as well as full frame cameras. The main point of my video is that you can't just multiply the focal length of a full frame lens when you put it on a APSC camera and you will get the same image as you would on a full frame sensor. A 14mm FF lens on a APSC camera will look different than a 21mm lens on a FF camera. Another thing to note is that my FF cameras are 45MP and Nikon doesn't make 45MP APSC cameras. Thanks again for your comment.

[@arboldechorizos]

Great video man! I have a question: Are APS-C specific lenses (for example, kit lenses) designed with this in mind and not need to "crop" the image or they behave the same as the lenses designed for full frame?? I mean, if the lens itself is designed to cover 100% of the APS-C space, it would be still considered a "crop" of the optical image produces by the lens?

[@thephotographytoolkit]

Thanks so much! To be totally honest, I am not sure if the what the lens manufacturers have in mind when designing the lenses. I am guessing that they are trying to replicated the field of view and the actual characteristics may vary. A 50mm f1.4 lens from one manufacturer (like Nikon) will look slightly different than a 50mm f1.4 from another manufacturer (like Sigma) even when put on the same camera. The only thing that should be the same is that they have the same field of view. And even that differs because manufacturers will round numbers. For example, the Nikon 50mm f1.4 lens has a field of view of 46 degrees and the Sigma 50mm f1.4 has a field of view of 46.8 degrees. I did do some tests where I used an apsc lens on a full frame camera in full frame mode to see the vignetting and then overlaid images capture on a full frame lens and scaled them down. The vignetted image captured on the apsc sensor at 18mm had the characteristics of a scaled down 27mm full frame photo. But the full frame 27mm photo had a blurrier background even though it was captured at the same aperture as the 18mm apsc image. These results are consistent with what I shared in the video. So it does apply when working backwards with crop lenses. Does that make sense?

[@arboldechorizos]

Makes sense, thanks!

[@thephotographytoolkit]

@@arboldechorizos Happy to help!

[@mohannadmalik5373]

That summ it well, correct me if i am wrong, we are only talking about aparture depth of field due to change in focal length of apsc and full frame does that affect landscape photography? I think i don't need shallow depth of field when i am shooting at f10 and beyond and i still get full frame image size on apsc wide angle lens

[@thephotographytoolkit]

I think if you are using really small apertures you probably won't see much of a difference.

[@mrsunesis]

So insightful. Thank you. Kindly help with the title of the soundtrack at 10:19 and where I can get it. I will really appreciate that.

[@thephotographytoolkit]

Thanks so much. The soundtrack is 'Find Your Way Beat' by Nana Kwabena. If you click on your icon in the top right corner of your screen and select KZbin Studio, then on the left hand side select Audio Library, you can then search for Find Your Way Beat or Nana Kwabena. You can download the song and use it and don't have to attribute but you can see that I did attribute at the end of my video. You can also check out Nana Kwabena's KZbin channel: kzbin.info/door/R8WNU7NJOQYJMfQgBAUSqg

[@mrsunesis]

@@thephotographytoolkit thank you!

[@rottenbassist777]

So full frame camera having more lens options, is better for milky background than a crop body?

[@thephotographytoolkit]

Essentially yes. But also no. Let's start with how a full frame camera will NOT give you blurrier backgrounds. The first thing is that a crop sensor camera will just give you a crop of the full frame sensor image. So if you have the two cameras from the same spot with the same lens, the background blur of the crop sensor will be exactly the same as the full frame camera. The field of view will not be the same so the framing will look different. This is because a crop sensor camera is just a crop of the full frame image. Now let's look at how a full frame camera WILL give you blurrier backgrounds. You will get blurrier backgrounds when capturing similarly framed images. Let's look at this example: let's say that you captured a head portrait with a full frame camera with an 85mm F1.4 lens. Now you want to capture the same framing with the crop sensor camera. To do that, you will need to move backwards. Because you are moving further away from your subject, this will lessen the amount of background blur. There are a number of factors that affect the amount of blur in the background including the distance from the subject, the lens focal length, the aperture of the lens and the construction of the elements in the lens. So if I want background blur, I start by getting as close as I can to my subject and that is easier with a full frame camera.

[@dmitrypovyshev6756]

Did the same test with a sony 7r4 camera and a 20-70 lens. First I shot in cropped mode at 20mm and then in full frame mode at 30mm. No difference in terms of perspective. There is a difference only in resolution and detail. Plus the lens profile in lightroom doesn't work very well in cropped mode so there is a little cushioniness. If you don't move the camera, nothing will change.

[@dmitrypovyshev6756]

I see what's going on. You changed the focus point and at such a close distance the perspective around you changes a lot. In addition, when you change the focal length when shooting such close objects, the internal distortions of the lens become very visible, they also make a difference in your 14 and 21 mm. Try also shooting some interior with the focus point in the same place and without moving the camera.

[@dmitrypovyshev6756]

As far as bokeh is concerned, everything is correct. When we shoot at 21mm the focus point relative to the sensor becomes closer and at the same aperture we get a more blurred background. I'm writing with a translator so it may not be very clear)

[@thephotographytoolkit]

@@dmitrypovyshev6756 Camera was focused at the very beginning and then lens was switched to manual focus so the focus point didn't change at all.

[@thephotographytoolkit]

Thanks for your comment Dmitry. That is super cool that you did your own test too. I definitely didn't move the camera and there was a difference because I am using a different focal length. Different focal lengths will give different looking images. All I am saying is that you can't just multiply the focal length of a full frame lens when you put it on a APSC camera and you will get the same image as you would on a full frame sensor. A 14mm FF lens on a APSC camera will look different than a 21mm lens on a FF camera. That is because they are different focal lengths. If you put that 21mm lens on the APSC camera you will get the same look as the FF camera with a 21mm lens when you crop the FF image.

[@thephotographytoolkit]

@@dmitrypovyshev6756 Totally agree with you when it comes to bokeh. The translator you are using is doing a good job. I appreciate the comments! Thanks

[@thepickyreviewer]

Excellent explanation

[@thephotographytoolkit]

Thanks so much!

[@bulboes]

Thanks, convincing set-up & test - never saw anything about the crop/aperture-thing that clear.

[@thephotographytoolkit]

Thanks so much. I am happy that it was clear and convincing.

[@alexgoriatchenkov]

It was Great time to watch your explanations. Some photographers continue to say only Length (MM) exchanged in Crop sensor cams and F keep the same value. So now will argue with them (50mm F2,8 =. 75mm F4,2) Thank you.

[@thephotographytoolkit]

Thanks so much Al.I'm glad it was helpful.