Full frame vs Crop sensor: Why CROP FACTOR is almost USELESS

Special thanks to Spencer Garn for the inspiration for this video!
Let's talk crop factor, specifically with regards to full frame vs APSC crop sensor... how is it calculated, what effect does it have and why it's as useful to photography as bubble gum is to space exploration!
We'll be comparing a crop sensor APSC camera (Sony a6000) and Full Frame camera (Sony a7c) to see how the focal length and aperture affect the images on each sensor size.
Enjoy!
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[@DigiDriftZone]

Woah woah woah, ISO is calculated per square inch. So yes, ISO20 on a phone is not the same ISO as on larger sensor sizes, it's like converting from cm to inch. The formula isn't multiplying by crop factor though, it's ISO multiplied by (crop factor * 2). For example, if we take a Fuji X-S20 APS-C and a Sony ZV-E1 full frame and their native ISOs, if we convert them for the respective crop factor equivalents: 1. APS-C figures - Fuji: ISO 1,250 (640 for DR 400%) -- Sony: Dual native at ISO 200 and 4,000 2. Full Frame Figures: Fuji: ISO 4,000 (2,000 for DR 400%) -- Sony: Dual native at ISO 640 and 12,800 You can try this in practice, it absolutely works. This is a common misunderstanding but your friend was right. Tony explains why this is in detail here: kzbin.info/www/bejne/bHrQZYqVbsefnrs

[@okaro6595]

Nobody talks of equivalent exposure. If you want equivalent noise levels and depth of field you need to apply it to aperture and ISO. Those equivalences are important to know or otherwise you will buy completely wrong lenses. You do not need them on the field if you know your equipment. Those images are entirely different. One has far more background blur so the comparison makes no sense. You should stop the full frame to f/5.6 and raise the ISO to 200 so you would get the same results. The whole issue is how to get same results on APS-C and as full frame. Northrup says use the crop factor on aperture and crop factor squared on ISO. IMO that is too complicated. Just adjust both by one f-stop or maybe one and a third. That is if you want to recreate a full frame look on APS-C you need to apply the crop factor on the focal length, open aperture one f-stop more and use half the ISO. Now in practice in many cases you do not have a lens that could do that. It just show you cannot do same with a $500 camera as with a $4000 camera. You so almost got it. You said you need to change the ISO but then you rejected it. You were on the chalk lines and stopped.

[@andreas1701d]

Hey thanks for watching! My goal here was not to compare the "look" of each shot, meaning the depth of field difference is irrelevant. The goal was to have the same exposure. The crop factor does indeed affect depth of field, but not the amount of light gathered by the camera which is what iso essentially modifies; it's an amplification of light. An exposure of 1/50, f1.8, iso 200 will allow the same amount of light into the camera regardless of sensor size. This is essential for comparing how much noise both cameras produce at the same exposure.

[@DigiDriftZone]

@@andreas1701d That is wrong ISO is calculated per square in, the ISO number means nothing if you don't know the sensor size. The crop factor absolutely affects the light gathered. A Full Frame sensor captures 1.5x more light, because the sensor is 1.5x larger, all else being equal. For example an f/2 lens on full frame captures 1.5x more light than an f/2 lens on APS-C. The reason you are seeing an exposure difference is you forgot to apply the crop factor to the ISO which again is per square inch. So electronically, ISO200 on APS-C is identical to ISO600 on full frame - same exposure, same noise, same light gathering, etc (assuming sensor technology of the same generation). If you don't apply the formula to ISO you are artificially reducing your Full Fame sensor sensitivity by 1.5x.

[@brotherted9212]

Crop factor relevance: Exposure? No. Focal length? Yes. Aperture? Yes.

[@RockWILK]

I find this such an interesting subject, because so many people on KZbin completely disagree with you, but what I most agree with is that you should just get a lens that fits your camera, and if you like the way it looks, tell stories with it. And if you like the way it looks on a crop sensor camera, and you upgrade to a full frame, then yeah, maybe you need to find the equivalent focal length, but at the end of the day, just use what works for your particular camera, and make art.

[@andreas1701d]

Yep, exactly the point. It's way too easy to get caught up in numbers and spec sheets and forget these are just tools; especially for a gear geek like me lol. Get the tools that get out of the way of you creating what's in your imagination 😉

[@RockWILK]

@@andreas1701d I totally agree. I spent the last 18 months shooting a feature-length movie on my cell phone, with obviously one focal range, and it looks pretty awesome. I think once we accept the tools that we have, we can start to tell the story. If we get caught up in the gear, we never get to the art.

[@DigiDriftZone]

kzbin.info/www/bejne/naqVeIObbd6VZ5I < Here you are running your APS-C at ISO100, if you want to use the *same* ISO level relative to the sensor size, you MUST set your full frame to ISO300, then you will see the exposure change. You are electronically setting your Full Frame sensor to a sensitivity 1.5x less than the APS-C sensor, this will result in a lot more noise on your APS-C and not a comparable image.

[@goodmythicalmukbang3757]

You forgot the crop factor on your wallet

[@andreas1701d]

Hey thanks for watching! Haha true... That's why managing that gear acquisition syndrome is important in this space. Buying/selling used gear helps a ton though.

[@goodmythicalmukbang3757]

@@andreas1701d very true! Older cameras do not magically suck all of a sudden just because you saw a new or better one.

[@andreas1701d]

@@goodmythicalmukbang3757 precisely! In fact that's why I made my latest vid about Sony APSC cameras. Even the old (by today's standards) nex-5t and a5100 are still terrific cameras, especially for the price! Same goes with something like the a7rII. For all the flak they've taken about missing features over the years, many Sony cameras were ahead of their time when they were released.

[@kneegrease]

Sensor size does not effect depth of field.

[@andreas1701d]

While not necessarily directly responsible for a shallower depth of field, a larger sensor allows you to shoot the same photo at a longer focal length (retaining the same field of view), resulting in a shallower depth of field. In other words, a photo shot on full frame at 75mm and f2 will have shallower DoF than the same photo shot at 50mm f2 on APSC.

[@thedronemediacomvancouver4976]

Lol! Luv the finish..

[@Server16116]

Wow thank you so much for this video! That mmcalc site is amazing and makes things very simple. However, I did have one question - I understand how exposure/light stays the same for the LENS regardless of APSC vs full frame, but does the size of the sensor itself add anything for the exposure? I have heard bigger sensor = more light picked up, but I didn't know if that was completely made up. For example, which would give you a better exposure considering the same iso values - APSC + 16mm F1.4 vs Full Frame + 24mm F1.8? (assuming you are shooting on prime lenses and not changing the field of view, and shooting at maximum aperture (F1.4 on APSC and F1.8 on FF). Thank you in advance for the explanation!

[@andreas1701d]

Hey thanks for watching! Comparing sensor sizes doesn't change the exposure. It only changes how sensitive a sensor is to light. That's why you hear that full frame "gathers more light". It's simply a larger surface, physically. This translates into a cleaner image, meaning less noise, if all settings are the same. For example, say you have an apsc camera shot at 16mm f1.8 iso 1600 with a shutter speed of 1/50 and a full frame camera shot at 24mm f1.8 iso 1600 with a shutter speed of 1/50. The "brightness" (or exposure) will be identical. What will be different is that you'll have less noise produced by the iso 1600 on the full frame camera. I also have a video comparing the noise between full frame and APSC if you're interested: kzbin.info/www/bejne/r5LKYoGQhNh8sKc Hope this helps!

[@Server16116]

@@andreas1701d Ah okay, thank you very much for the explanation - I think I was inadvertently mixing 2 separate categories - exposure "brightness" vs noise. And I guess it would be difficult to determine which would contribute more to give the better/cleaner image - wider aperture, say F/1.4, on APSC, vs say F/1.8 on larger sensor. Especially if both were shot in less than ideal lighting, say for indoor shooting or evening photography. The reason I was asking is because I myself was trying to decide whether to go full frame or stay APSC. The cost and size difference is great - for example great quality lenses on APSC are tiny with very affordable costs (see Sigma 30mm F1.4), even with an amazing F1.4 aperture. On the other hand, getting a lens of a max aperture of F1.4 on full frame would cost 2-3x and be much larger (ex Sony 35mm F1.4). So that wouldn't be an option for me, because I definitely consider size/cost to be a significant factor. However, something such as the Rokinon 35mm F1.8 would definitely be an option for me - small, not overly expensive. But it's F1.8, not F1.4. So I guess what I'm trying to ask - which would be more important to producing a brighter and cleaner image in less than ideal lighting - a wider aperture of F/1.4 (as opposed to F1/.8), or less noise with a full frame sensor (as opposed to APSC)? And yes, I did see your noise comparison video and gave it a like - awesome how you can crank up the ISO on full frame!

[@andreas1701d]

@@Server16116 in fact I made the same switch. I had the a6400 with the Sigma 30 1.4, Sigma 16 1.4 and Tamron 17-70. I switched that setup out for the a7c, Sony 20mm f1.8 and Samyang 35mm f1.8 (I also picked up the Samyang 75 1.8 and Sigma 28-70 2.8 since). There is 2/3 of a stop of light difference between f1.4 and f1.8. So let's say you shoot an APSC camera at f1.4 and iso 1600, you could get the same exposure on full frame shooting at f1.8 and about 2500 but because it's a full frame sensor, the noise shouldn't be a problem. In my review of the Samyang 35, I actually have some comparisons with the Sigma 30 at about 12:30 or so. kzbin.info/www/bejne/mafCamqwe7Fgl7M

[@Server16116]

@@andreas1701d Great, thanks so much! I have a similar collection, except I got the A73 - Sigma 28-70 2.8, Sony 85mm 1.8, Samyang 35mm 1.8. I was wanting to get a wide angle lens next - was debating on the Tamron 17-28 2.8 vs Sony G 20 1.8. Probably leaning towards the Tamron to get that extra reach. And I'll definitely check out your review video as well!

[@andreas1701d]

@@Server16116 I debated the same (17-28 vs Sony 20). I ended up with the Sony and it's a near flawless lens. I figured I can deal with going from 20 to the 28 of the sigma. Review on both of those coming soon 😉

[@afferist]

big thanks, mmcalc dont work

[@andreas1701d]

Hey thanks for watching! Seems like it was shut down a few months back. That's unfortunate. Here's a good alternative: www.omnicalculator.com/other/crop-factor

[@afferist]

@@andreas1701d It works, thanks!

[@WilliamWallaceRoss]

DSLR is a dying breed, at least around here in my neck of the woods, mainly because price and those who control those prices.....they aren't made in the U.S.A.......