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

This is a very long way of saying the “boxes in boxes” diagrams are accurate for representing sensor FOVs. 😂
It is nice to see someone cover speed boosters, tho.

Will a 35 mm Apsc lens will have exactly the same field of view of 35mm when used in an Apsc sensor camera?

So...if I use a crop-sensor EF-S 50mm lens on a Canon APS-C camera, do I still need to multiply 50 by 1.6? I heard that I do. You'd think they could/woupd build an APS-C lens that will make a 50mm FoV at 50mm, rather than at 35'ish mm. As a consumer, having to do the math [even on a crop sensor camera lens] is a real pain when learning photography. I would rather have the actual, modified, true FoV printed on crop sensor camera lenses rather than what it would be if on a full frame camera. Aside from certain crop sensor benefits, full-frame is just the way to go from the beginning, simply for actual FoV stated on the lens. The extra reach of APS-C is beneficial at times, sure, but it's too much of a hassle having to do the math until finally, eventually, memorized. 🤣

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

Mt Jazz hands 😂

I learned something new

✌

You still apply the crop to the crop lens on a crop body for the field of view equivalent. 35mm on a crop despite the lens being made for crop or not still is equivalent to what ever the crop is.

Awesome explanation man , thank you 😊

Nice mechanistic illustration, thanks.

Dislike, twice. Priceless.

So if I put a 30mm apsc lens on an m43, the 30mm would be converted to 45 vs a 30 full frame lens which would be 60mm on the m43?

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.

I wish i found this video before i bought my lenses

All other videos on this topic should be deleted.... Because this video is all anyone needs
.🤌👏👏👏👏

Thanks that explains everything.

This is excellent, thank you.

Some say that you have to apply crop factor to the focal length even if you are using a lens made for that crop sensor, is that true?

This video deserves a million views. Thank you sir.

You hit the nail on the head. No one is talking about crop lenses on crop bodies. Just always switching.

So back to the side view diagram of a man. If a 50mm full frame lens on a full frame body shows the full person head to toe at a given distance.

Does a 50mm crop lens on a 50mm crop body show the full person head to toe as well at the same given distance?

Your greeting does indeed sound like somebody is stepping on your balls in the start of every video :D lol. Now since you pointed this out, I cant unsee that :D Top notch content as always!

Wow that got pretty complex at the end there but I think I got it. I watched this because in my testing at home, a Canon EF-S lens on my crop sensor shows the exact same image as an EF lens on the same camera. I thought that the EF lens would be visually zoomed in, but it isn’t. So then I don’t have to do any math conversions if I just want to understand how a lens will perform visually. Crop & full frame lenses look identical on my crop camera.

I think I just got my brain crop factored!!!!

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

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

I'm thinking of buying my first pro camera. Sony A1 and 24-70 f2.8 GM II. Bit of a newb here. I was wondering what a crop factor is. 🤣🤣🤣

If I use a 25mm MFT lens on an MFT camera, will that field of view be the same on a 25mm Full Frame lens on a Full Frame camera?

Best explanation yet! Thank you!

Is The perspective distortion is the same on apsc vs full frame or its different ?? A 56mm lens for apsc have the same perspective distortion as a 85mm on full frame ??? Not the bokeh i mean the compression do i get the same perspective distortion with a 16mm on a apsc as i get with a 24mm lens on full frame ??

Great video Gerald Undone! Although I got confused at the end. If an APS-C (or a M4/3 ) lens has a narrow FOV than a full frame "in the same Focal length (I suppose)", the rectangle or circle crop does make sense, and it seems the quickest and best way to demonstrate Focal length equivalent from different sensor size. A little help please!

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

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.

Can someone explain how a smartphone camera with a 4.23mm lens at f1.5 will give you ABOUT the same look as a camera with a 27mm at f5? Given that the DSLR has a 1 inch or larger sensor, from an optics point of view? Is it all computational photography? How can a tiny lens and camera achieve amazing pictures these days.

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 😐

There's something I don't understand, you said the difference between a FF lens on a FF body and a cropped lens on a cropped body is that the field of view is narrower, but isn't that the same as a crop since we see less of the image ? I mean when there is a crop isn't the field of view also narrower ? So what's the difference ? Or did I miss something ? I hope my question is not dumb

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

A full-frame lens on an APS camera will just behave more like an APS lens (ie. same 35mm focal length) with the same FOV & Fstop except there is more unused image/light bouncing around the insides compared to APS lens on APS camera. The first thing the manufactures do is design lenses in similar zoom range as full-frame lenses except they divide the mm by the crop factor ie. Instead of 24-75mm F3.5-5.6 for full-frame, they make a 15-46mm F3.5-5.6 so in practical terms the photo's they produce look very similar when the lenses are at their widest & when the lenses are zoomed in, only the megapixels, dynamic-range, RAW noise & clarity of each may differ depending on the hardware used. You could probably not tell the difference when printing to a 6"x4".
There are FF lenses that don't have APS or smaller equivalents & using a FF lens with a smaller sensor will reduce the wider angle of view but enhances the telephoto range (any overlap in the middle can be made to look the same, eg. 56mm FF = 35mm APS-C). What does change is the equivalent DOF & Fstops which are harder to achieve with small sensors. A smaller sensor can get the same listed Fstop in terms of light on the sensor but it has a much higher Fstop number (eg. f7 vs f4) in terms of DOF. Portraits with f1.4 to f2.5 primes are done with FF cameras because why would you waste the lens capabilities.

Older P&S cameras with 1/2.5" sensors often showed the equivalent 35mm values so 30-240mm f2.8-6 reported by the camera was actually a lens doing 5-40mm with brightness of f2.8-6 compared to the sensor but DOF equivalent of a 35mm lens doing f16.8-36.

DOF= depth of field.

Great video! 👍 While I understand crop modes, what I don’t fully understand is how does it affect video quality in crop mode verses full frame ? 🤔 Thanks 😊

Sadly, my english is not perfect, and I dont understand well. So! If I want the same Full frame 16mm look on my APS-C camera, can I use a 16mm APS-C lens or should I use a 10mm Full frame lens?

Very Clever. I get it. Great demonstrations

I don't think the flashlight example is really an accurate representation of what's going on. Lenses designed for larger sensors don't spread the same amount of light out further, they allow additional light in to cover a wider field of view. A more accurate demonstration would be to mask off part of the flashlight to show a smaller circle of light for the crop sensor. The brightness at the centre will remain the same.

It seems to be a common misconception that lenses for crop sensors somehow reduce the image down to a smaller size. Imagine looking through a hole in a wall. If you look straight through it you'll see the scene on the other side - that's the crop sensor angle of view, if you move your head to the left and right you see more of the scene, that's full frame, move it a bit more and you see more, that's medium format. At no point does the scene enlarge or get brighter.

I don't know if I'll ever be able to understand this 😕

Thanks for this. It's really annoying that crop factor cameras exist. I was ignorant when getting my first camera (XT3) which I really love but I always have to do these 1.5x on the lenses to know the actual focal length. Really annoying

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!!

This explanation was amazing. I still am not sure about how this works on MFT lenses on MFT bodies. Will my 42,5mm lens on my GH5 be equivalent to an 85mm lens zoom wise, but still have the "look" of 42,5mm? Or would it also have the look of an 85mm lens?

thank god someone explained it

Gerald Holmes

This hurts my tiny little lizard brain, but I'll try to catch up! is it possible for future Gerald to try this explanation again in smaller words for slow people? (asking for a friend!)

I don't know if this is possible but I have the Sony aps-c 35mm f1.8 prime lens currently with my Sony a6500 body which of course gives me 50mm equivalence however is it possible to get native 35mm were I to use for example the Sony a7c full frame body? I mean is there a converter out there or is my 35mm lens a 50mm forever?