Crop Lenses on Crop Bodies: How It Works vs Full Frame (APS-C & M43)

[@guymross]

It's amazing that Gerald is basically the only living human person capable of explaining basic photography and videography concepts. Thank you Gerald.

[@TonyRush21]

In everything applicable on earth there has to be a top person... I guess Undone is the one. 😊

[@DesertCookie]

The amount of people I've recommended this to on Reddit to clear up their confusion is... at least four. Phantastic explanation. I come back to it now and then to make sure I don't get mixed up with my terminology.

[@ShaayarAajnabee]

OMG.. yessss!. You answered the questions I had in my mind. I felt like generic boxed illustrations were misleading on internet when they compared the APS-C body with full frame lens and vice versa. But never got a good explanation of focal length and field of view of APS-C body with APS-C lenses. You explanation is perfect. Although I been into photography since last year, bought a dslr myself, used it, and have watched lots and lots of tutorial videos, camera reviewers, etc on youtube. However, I just stumbled upon your channel few days ago and I have learned so much from watching your videos over the last few days. Your videos are loaded with detailed information. There is no unnecessary long b-roll intro. There is no time wasting. You get right to the point and sum it up just enough in such short time. I can't thank you enough. Usually with other reviewers and videos I end up skipping and fast forwarding. But with your videos, there is no space to skip forward because every second is to the point and important. In fact, I have to replay certain things just to wrap my mind around it. I like how you cover so much in short time. I can't thank you enough. Please keep making videos like this. If anyone needs legit answers about photo/videography I will be directing them to your channel. Subscribed!

[@geraldundone]

Thanks for the great review! I appreciate your kind words and encouragement. Thanks for taking the time and commenting. 👍😊

[@erlendviken6412]

Really high on knowledge! Me: pause, think, replay. Repeat 😂😂

[@romariop6016]

Too many youtube videos are confusing people about the crop factor always mentioning it even with apsc lenses designed for apsc cameras Im glad i found your video to clear what mixed up knowledge i had before

[@okaro6595]

Crop factor applies on all lenses.

[@Fast58Eddie]

This a fantastic explanation without a lot of technical facts. It was perfect for for someone to understand the different sensor sizes. Thanks!

[@Dave_Stafford]

You've a real talent for taking this tech stuff by the scruff of the neck and knocking the complicated out of it.. love these, ..educated and entertained. Thanks!

[@pablopugliese]

I am so glad that you are bringing real optics talk into youtube, every video I see from you surprises me even more. Your explanations and how you organize your content is absolutely amazing! You get to the core of things, where science becomes accessible for practical application.

[@geraldundone]

Thanks a lot, Pablo! That means a lot. Cheers! 😃🙏

[@dajael]

My Man, you somehow got about an hour's worth of information into that 09:23 window. I don't know exactly how you did it but you did! I'm gonna go watch it again and maybe even a 3rd time if necessary ;-) Great job!

[@reginaldworthington7558]

D. Jason Ellington Gerald uses a speed booster for that too!

[@tomwd.2825]

...despite the fakt that its filled with mistakes...

[@ariesmight6978]

@@tomwd.2825 Can you provide us with all or. At least most of the examples?

[@tomwd.2825]

@@ariesmight6978 there is no loss of light nor loss of sharpness from useing a FF lens on crop body. A 35mm is a 35mm on a crop body, half true. Modern cameras have a setting for adapted lenses and they work with the settings to get a proper crop picture looking like it should if you used a native crop lense... grab a fuji cam and you will see. FF lens on crop body uses only the inner circle of the lens which is the better quality. No blurry corners or sharpness loss in the corners there. Speedboosters working like a magnifiing glas, noting more...but with all the downsides of it. Less quallity. A 35mm specificly build for crop is still a physical 35mm but optimised for crop sensor. Physics dont change from useing another body. This is why its hard to build good quallity wide-angle for m4/3 because its the same build as for a fullframe. A 17mm M4/3 is a 35isch fullframe aperance but physically it's a 17mm, sobits very hard to getbthe same quallity build. Is this answering your question?!

[@ariesmight6978]

@@tomwd.2825 Thank you for the constructive and informative response. There are Soo many toxic people in the comment sections.

[@danipphoto]

This video was INSANELY helpful. I appreciated the visuals and illustrations more than you know, I recently discovered that I may have ADHD so I need this kind of content, I struggle to just listen to people talking! I have never come away from a video without questions before. Thank you so much!!

[@geraldbertram7718]

By far one of the best explanations of this subject I have seen yet. Well done, Gerald. By the way, you have an AWESOME name

[@geraldundone]

Thanks a lot, but I think you might be biased about the name part. 😜

[@anonymousl5150]

Except Gerald is wrong. The light density of a sensor is purely determined by the f stop. A f/1.4 full frame lens on either a ff sensor or an apsc sensor will look equally bright on the image. He is confused because he is thinking about how speed boosters take extra unused light (from using ff lens on an apsc sensor) and concentrate that extra light for a higher f stop but that logic isn't why full frame lenses sometimes look less sharp on apsc sensor. The real reason is when you use a ff lens on an apsc sensor with higher pixel density and lower pixel pitch, which demands higher resolution. So your same lens will look more sharp on a 40 megapixel full frame than a 26 megapixel apsc. But let us assume both the ff sensor and apsc sensor have the same pixel density (60 megapixel ff vs 26 mp apsc). Then what you will find is that the full frame lens is exactly as sharp in the center and even sharper on the apsc edge because the weakest part of the image circle (edge of full frame image circle) is cropped away and you are left with the midframe edge of full frame (which would be outer edge on apsc).

[@gmolina]

If you can't explain something with simple words, then you don't really understand it yourself. I already knew everything you said, but I watched anyways. You've done an outstanding job explaining this subject. I will refer this video when people ask me about this topic. You just gained a subscriber and I hit the like button thrice ! Cheers!

[@geraldundone]

Awesome! Thanks so much. That's what I was hoping for--to make for a decent reference video. Glad to have a new subscriber. Cheers! 😃

[@RenatDavodov]

When someone (like me) want's to learn how things ACTUALLY work and not just the basics, your work is golden. Thank you a lot.

[@blueckaym]

at 7:35 starts the correct explanation! A Xmm focal length lens is such regardless of being designed for Crop or FF. The cropped lens only have different design so that they save some glass, since there's no need to cover bigger projection. Same goes for F-stop f/1.8 in crop-lens is exactly the same as f/1.8 in full-frame lens - as it's simply the ratio between the aperture & the focal-length, and since focal-length is the same then the aperture is the same at given f-stop. Ie it produces the same depth of field (or bokeh) (ignoring the actual quality of image and T-stop). The only difference is the size of the projection and the size that you can capture from this same projection - ie the sensor size. The flash-light example at 5:12 is extremely misleading! It can easily fool you to think that crop-lenses for same given focal length have some kind of speed-booster inside them, which they don't.

[@CrescendoKeysChannel]

You said what I want to say after watching this.

[@PeterMKent]

Great effects and very entertaining, I almost didn't watch this one but really enjoyed the explination. My issue with "crop factor" has always been its reliance on first understanding a lens' FoV on another body. Again if everyone started naming sensors by their diagonal measurement we would have far less confusion, because a lens that measures the same as the sensor's diagonal provides a neutral "Field of View". That's a 43mm on a "Full Frame", 28mm on an APSc and 21mm on a Micro FourThirds. If you want a Telephoto you would multiply by 2; which is 86mm on FF, 56mm on APSc and 42mm on mFT. A wide angle would simply be divided by 2 so a 21.5mm on FF, 14mm on APSc and 10.5mm on mFT.

[@geraldundone]

I'm glad you did watch it, Peter! 😃 Thanks for the comment and for sharing some notes on FoV.

[@danggood]

So - you told me to give you a minute so you could grab your flashlight - and i was like, "why do people do this in videos? Just go get it and edit it so it's like you always had it ready. you don't need to tell me you forgot to grab something for a shot, just edit. and then you grabbed it from your seat and it was the best thing ever. unexpected magic. i was glad you didn't cut that out. thanks Gerald.

[@atlantamx3]

Seriously- You should have a zillion subs. This is crazy. Loving these videos .

[@cosmogang]

The flashlight grab was everything. 💓

[@michaels8597]

Gerald Undone is killing it with some FACTSSSSSSSSSS..Bow down those who keep trying to befuddle,confuse,and mislead the public...

[@tremaincheerful4189]

Your explanation is the clearest most concise and logical I have ever found on this issue. Your flashlight illustration perfectly explains why we do not see sharper edges in our photos when using FF lenses on crop sensor bodies. The light focused by the lens is diffused over a larger area, more of the detail the lens is able to focus is wasted outside the sensor area. This is born out by rigorous tests by DSO mark, as referenced in Tony Northrup's excellent video on this subject. "Perceived" megapixels will be less when using FF lenses on crop bodies, particularly if they are poor lenses to begin with.

[@Photographicelements]

Thank you for putting everything about sensors into one video; this is the perfect reference. I am sending this link next time, instead of lengthy explanations. #filmschool

[@mtaha9477]

Thank you, I moved from a nikon D810 to a fuji xt20 and your video helped me make more sense of what I can do with a crop sensor. Cheers.

[@HackMyControlSystem]

Congrats on achieving 'Professor' status and thank you for clarifying speed boosters!

[@antoniogil5156]

Subscribed. You just simply revealed to me in great style the reason why my 40 year old 135mm Minolta lens adapted on my m43 body produces such low light and grey pictures. Well done, mate.

[@lucykaleisky]

finallllly the answer of my question. Thx Gerald. Short and clear as usual (two years later x) )

[@TheOnlyGuess]

This is the topic that I have been discussing with so many photographers who keep saying that full-frame lens will provide more zoom on APSC cameras which is illogical. Thanks for the video that AI helped me find it

[@mauibuilder1239]

Wow....great explanation. You've UNDONE a lot of misconceptions floating around.

[@geraldundone]

I'm going to have to steal that. 😃

[@retalt]

This has been the best explanation of full frame v Micro 4/3 I have seen yet. Really nicely done. Thank you.

[@Quarmacy]

Thank you so much. I was so confused by my own research. Now I can rest easy using my 50mm full frame lens on my APSC camera.

[@johndonaldson5126]

Actually that is the best explanation I've seen. Thank you.

[@RockyColaFizz]

Some people simply have an amazing knack at explaining things.

[@AWAShowme]

This video deserves a million views. Thank you sir.

[@dunnadidit]

Great video dude! My favorite thing to see in the comments is when people say you have to crop the aperture number too... I mean I get where they're coming from but it's not technically right.

[@geraldundone]

Thanks, Dunna! Applying the crop factor to the f-number is a good shortcut to figure out your relative depth of field though, or rather where you'd have to set your cameras to match each other in terms of depth of field. Easier than doing angle of view math. 😃

[@melvinch]

They have been brainwashed by that Phony Northrup prick.

[@timberwolves100]

The people that use Northrup math confuse 'Total Light Gathered' VS. Aperture. Aperture is determined by the lens and only effects exposure of an image in terms of light. A bigger sensor will collect more light. BUT it also requires proportionally more light to get the same exposure. You can't compare Apertures across different formats because the lenses need to be bigger/smaller to accommodate the sensor size. The extra light gathered from bigger lenses with bigger sensors does improve the ISO Performance and generally results in a less noisy image. But NOT related at all to the Aperture across different formats. It's ok to point out that depth of field will be different on different sensor sizes but saying you need to include Aperture into an equivalency discussion is flat out false. Real tests will prove it.

[@PerryMulder]

Tnx for this! They just keep getting better! Keep'em coming man!

[@nbdvisuals]

Now this really got UNDONE!! WELL DONE!!

[@Keepingitsimp]

WOW! I have never had it explained this way, thank you!

[@terryd8692]

Came across one of your videos yesterday and was really impressed. There are a lot of nails being hit on the head in a short amount of time.

[@its_arunprakash]

I don’t know why schools won’t teach this subject of optics which is so much important in real time.. Well done.. and thank you for bursting misconceptions..✌🏻✌🏻

[@peepers4763]

Your editing choices are so good. Transitions and inserts keep things interesting. I see and appreciate your choices. Remind me never to get in a verbal argument with you. You’ve already won 😉

[@geraldundone]

Hahaha. This is a fun comment. Thanks for the compliments, mate. Much appreciated!

[@ifell3]

Genius, i'm watching in order but skipping back and i have to say what you are saying is what i've been trying to get my head around.

[@w2.ill_]

This video somewhat answered one question for me regarding how different lenses work on different sized sensors. I'm still wondering, if a cropped lens doesn't cover all the frame on a full frame sensor, why, when it does cover the whole frame on a cropped sensor, it's still cropped. For example if I have a 50mm APS-C lens on a full frame camera, it's showing a proper 50mm FOV but with a big part of the frame left out, but if I have it on a cropped sensor camera, it's still showing the 85mm FOV, even when it's covering the whole frame. Why couldn't the lens cover the proper 50mm FOV if it's designed specifically for cropped sensors?

[@BrendanCescon]

Hands down the best explanation of all this I've ever seen

[@curiousladyinla]

So so good. I get it now with your visual illustrations. I was not getting the instructor in class blabbing away about crop factor.

[@SteveMayedaTV]

Good stuff! I’m glad you can break it all down. I can’t break this down but I’ve know this forever and always hated the explanation. Anyway, you’re a genius man. I’m always amazed at how much you know and can explain.

[@geraldundone]

Thanks, Steve! That's quite the compliment. Really appreciate it and I'm glad you liked the video. 👍😃

[@JustinWheeler_LA]

Absolutely brilliant, as usual, Gerald. Finally feel like I get this topic. Thanks so much.

[@geraldundone]

Thanks, Justin! Happy it was helpful. Cheers!

[@ryansherrell]

This is great. I'm left wanting to know more about this and would love it if you had another video to further explain. It took a few videos to land here and I'm on the right path.

[@dj_ramo]

Where was this video my whole life!?! Thank you! Well said.

[@cpgr19]

The main misconception is that an 85mm full frame lens on a FF sensor gives the same result as a 50mm apsc lens on apcs sensor...That is why people assume that focal ranges change, because they link focal ranges to specific field of views. Lens makes should advertise lenses based on their fov and not focal ranges...

[@johnson280]

I was constantly distracted by thinking you MUST be a genius. :) You keep referencing with your eyes to some diagrams which weren't there while you recorded it. And you kept referencing to these with your eyes so naturally that I kept thinking, you could not have done this so well without rehearsing it like crazy. It's perfect and helped me to learn it!! But may be you are a genius and didn't rehearse it, I mean you also have an extendable 10-foot arm that you can bend over backwards...so what do I know!

[@geraldundone]

Haha. Love this comment. Thanks a lot. I don't necessarily rehearse, but I do have notes that I reference. I usually explain for as long as I can until I need to check my notes to make sure I didn't skip anything important. Then you'll see a jump cut and then I'll be back at again. Sometimes you'll see a jump cut because I said a word in way that sounded funny or garbled, so I have to do a retake. Which I guess ends up being a bit of unintentional rehearsal. 😃

[@LSteven2U]

Wow !! you got it in ... all of it : and after so many others, you made sense of that which is complicated, Clear and simple -thanks

[@CyclopsJoeVideos]

Awesome explanation man , thank you 😊

[@TerraThink]

Well done Mr Undone.

[@renealvarezyt]

Finally an explanation that makes sense!!!!! Thanks!!!!

[@lkoelker]

I'm looking into purchasing a Panasonic GH5 but I was a little concerned about all the boxes that you explained and the crop and all that stuff... Thank you for clearing it up for me!!! Awesome video, totally smashed that like and subscribe button.

[@geraldundone]

Thanks so much! Glad the video was helpful and happy to have a new subscriber. Cheers!

[@dominic-ryan]

I find the way you break information down SO much more digestible than others out there. In Tony's latest M43 bashing video he talks about how a FF lens will gather 4 times as much total light as that of a M43 lens of the same aperture. This I follow, however he then goes on to pass reference to how this results in reduced noise on the FF system without really stopping to explain the math behind it or what M43 sensor tricks can be used to mitigate it (such as higher base ISO or even dual ISO). If you ever had the time and inclination Gerald, I don't think (or at least am unaware) this topic has been broken down into layman terms like all the other pros/cons of FF Vs M43. Could well do with some Gerald treatment. Thanks for your channel!

[@geraldundone]

Thanks for the kind words and suggestion, Dominic. Really appreciate it. 😃🙏

[@newpageone]

Dude, thanks so much for saying that the focal length doesn’t change. I feel like that’s a concept that a lot of people don’t understand thanks to these diagrams and such. The lens is going to work the same, you’ll just see less of the image.

[@inpursuitofhappiness4873]

Really liked the point about focal length and field of view in comparing between FF and other formats. Thanks.

[@bobbytirlea]

Absolutely well explained! Thank you!! Optics are optics no matter what on all of the frames, and the crop factor (say by multiplying) applies only to the digital processing of the final image we see and perceive. Shortly, the 35 mm image cropped to 52.5 mm (for Nikons) will always be an optical 35 mm, processed and magnified to a 52.5 mm digital image.

[@tysonator5433]

A pretty good explanation of a common topic. I really did enjoy watching the video. Keep up the good work

[@robinschlolaut9529]

So far the best explanation I heard! Thank you for that!

[@Ladybirdsin16mm]

Thank you!!! My question is, a 90mm aps-c lens on a aps-c camera. Will that be the same field of view as a 90mm FF on a FF body? Or is the aps-c going to be about 135mm (1.5x crop)

[@okaro6595]

Why would it have the same angle of view? Of course it does not have the same. The idea that it would have is absurd. The sensor size affects the angle of view.

[@largeteezy]

This is literally the best and most clear explanation of crop factors that I have found on the internet. Kudos to you sir

[@trialerror7218]

that's some impressive video effects and quality.. and brilliant explanation!

[@KevinJennings42]

This was great! Thanks for bringing some clarity (and dare I say focus, maybe not) to this often confusing topic.

[@iamleon777]

Hi! I have a question that I can't seem to find an answer to. Partly because my lack of experience in the professional camera realm and partly because of the lack of information out there. I want to buy a Lumix S5 and I also need a lens for it. I want to film super wide angle at 4k60 ( so the image will be cropped ) and I am looking for a lens that will give me roughly the same image as an iPhone 11/12/13 on the ultra wide camera in video mode ( iPhone crops in ultra wide video mode ) and from what I understand the focal length of the ultra wide on the iPhone is 13mm ( in photo mode ). What lens should I buy for the S5 ( preferably prime ) for this effect aka iPhone ultra wide video mode ( 13mm cropped ). Thanks 😐

[@jeweljose1653]

Great demonstration! you cleared a big misconception I had! Thanks a lot!

[@skyrocker71]

thank you for the explanation , awesome and btw...that effect reaching ur flashlight :):):):)

[@geraldundone]

😃😜😄

[@bas2833]

I liked the video so much that I hit the like button 3 times. You're welcome!

[@pasinduwanniarachchi4992]

just wow man .just wow . Great explanation on speed boosters too .

[@HodajuciParadoks]

Best explanation I have ever heard.

[@geraldundone]

Thanks so much!

[@gregkarris6869]

great explanation. this guy knows his stuff.

[@2365Films]

EXCELLEBT TUTORIAL! Bravo - well done!!

[@BABBRANTECH]

This is the best and correct explanation, thanks. Now, i am confident about my thought on lenses.

[@jarofwhisky]

now i finally understand why my canon 24mm f/2.8 ef-s lens is way sharper than my 50mm f/1.8. this video was awesome

[@ankit-travelandgadgets]

Here comes the man who just "DRANK" THE cameras Lots of love and respect from indoa🙏🇮🇳

[@ozzythemighty2767]

Keep pushing out this kind of content plz.. especially updated ones. thq for the vid :)

[@Photographicelements]

Now that is REAL magic! (4:52) You can't deny it any more, I know you have actual wizarding powers!

[@kermitshamburger774]

You did a great job explaining this subject. Thank you.

[@idratherberidingnow]

Just found your channel, great information and your presentation is spot on. You have a new subscriber.

[@geraldundone]

Awesome! Thanks for the kind words. I'm always happy to have a new subscriber. 😃🙏

[@timothylatour4977]

Excellent video for several reasons, not the least of which is the way your graphics match your words. That must take quite a bit of time and talent to get those right. Thanks. (Not a Canadian but lived there happily for 7 years back in the 70's.)

[@raynjpg]

Thank you for this video. I didn't even know about speed boosters until I watched it. I'll keep them in mind when looking for my next lens. It would be great to buy a full frame lens that I can use a speed-booster to get the desired focal length now, and get that same focal length when I eventually buy a full frame down the line.

[@ottoespinalxx]

MAAAAAAAAAN! This is the FIRST video spoken in a caveman language I see about a very misunderstood topic! Loved it man! Your videos are damn amazing⚡️

[@bassem500]

Best explanation yet! Thank you!

[@JayMaasRecording]

Dude your videos are excellent, this was so informational!

[@geraldundone]

Thank you very much!

[@DavidKatz]

Love your videos Gerald. You rock so much!

[@PhanitKoomhin]

Nice mechanistic illustration, thanks.

[@anishfolorunsho]

You are the best Gerald. Thank you for this video

[@Metaldetectiontubeworldwide]

Best explenation ever !! no cropped version 🤔😂🙌 Just recalculating my ef lenses with viltrox m2 x 0.71 to the final crop on my freshly smelling GH5 todo a first testing and video (mayby) myself 🙌🤩💥... Had to check what ma man Gerald had to say about that ...😂🍻

[@stacy6903]

James Bond effect at 6:26! Sorry - couldn't resist. Excellent explanation Mr. Undone!

[@geraldundone]

It's totally Bond! 😃👍

[@stacy6903]

:-) Hey also, thanks Gerald for adding to my love or M43 with your talk of the telecentric optical path in a prior video!

[@chrisabboud3949]

Best explanation I've seen. Thanks.

[@rogerpingleton9199]

Incredibly good explanation!!!

[@farestabs]

Great explanation & awesome video! I appreciate the time you put into making this :) I have one question you didn’t exactly hit on in your explanation which is regarding compression. Compression goes up as the focal length of the lens increases. A 75mm lens has more compression than a 35mm lens does which means it pulls elements of the image closer together given the same perspective. Now how does a 75mm full frame lens compression compare to a 37.5mm MFT lens?

[@sg7608]

Great content. Thanks for the much needed info !! 😊

[@kennethbradley]

Hey Gerald, awesome video. Question: If I purchase and full-frame M Mount lens that is known for having a sharp center but softer corners and then mount that lens via adapter to an APSC camera, would I not have sharper corners and the same sharpness in the center? Or, is it that I'm losing sharpness throughout because the light is dissipating because I've cropped in? I'm currently using a Voigtlander M Mount lens on my Fuji and I see sharper results than some of my native fuji glass (that plus a more interested look in my opinion). What are your thoughts here and on mounting full-frame glass on APSC cameras? Thanks so much!

[@NYPeterP]

Flashlight is amazing! And theory. Thank you, Gerald!

[@nicolasguillenc]

so I like photos taken at 24mm in a full frame body, to get the same result optically, I need at 24mm apsc and just step further? I’ll have to watch this video like 10 times, I may just need to go shooting a lot and then choose the focal length I like the most in my camera Also I have a full frame lens for my apsc, it was cheap but dang you are the only person on KZbin talking about this

[@tm536]

Thankyou sir! This has always been in the back of my head

[@jjualvare]

When using a Sony E16-70mm f4 lens on Sony a6500 camera, am I getting the equivalent of 24-105mm lens or am I getting true 16-70mm on my crop sensor?

[@anaxios]

24-105mm equivalent. The focal length does not change, but the field of view does. His words.

[@richardbrown2290]

Great video. Lots of good information that is well presented.

[@powellfilmmaking]

This was awesome and super informative. Thanks!

[@HaydnRushworth-Filmmaker]

Absolutely awesome mate!