I have been having a hard time figuring this out. My camera (Sony Fs5) has a super 35mm. Would you suggest getting lenses for apsc/ super35 or full frame? This is in regards to the Rokinon cine vs veydra cine lenses.

Tony Northrup I'd get a good full frame body and a relatively cheaper APS-C body, with full frame lenses if I'm doing wildlife. My idea for a Canon wildlife setup: Canon 6D mark II, and Canon T7i, and EF 100-400mm f/4.5-5.6L II.

Hi Tony, So if one is using an full frame lens on a crop sensor body, but metering with an incident light meter, what effect might one expect in the accuracy of the exposure obtained by the meter? Thanks

Tony & Chelsea Northrup If I use a Ef-s 2.8 (crop lens on a crop body) will the bokeh be the same quality of a Full frame lens on a full frame camera? Or can u expect the quality of the bokeh to be the same as a 5.04 phot on a full frame? What would give me the best bokeh for my apsc sensor if I want to take great background blown out portraits?

Alright got the answer from one of your other videos thank u so much for your content. The xfactor applies to both crop and full frame lenses. Took me two full days to find the answer and clarify this lmao and it was on a 15 min vid on KZfaq. You guys Rock.

Thank you so much! I'm so glad we could help!

I wish Tony would stop with his multiplying aperture advice and simply explain it the way you do.

I can't comment on the T stop thing but the exposure IS affected, why? ISO Aperture = focal length/iris diameter (the openning) And since a crop sensor can't collect the whole light that enters through a FF lens Iris, An image taken on a full frame body with a given lens at given exposure settings, is ONE STOP (or more) brighter than the same image taken on the same lens with the same settings on a crop sensor. But why do they still look even in brightness? ISO 100 on APSC = ISO 200 FF equivalent. The explanation of the noise difference.

+THEKMT6 That's incorrect. Exposure is not effected by a crop sensor for the same reason that exposure is not effected when you crop an image in post. It doesn't matter that part of your image has been trimmed off or not because the intensity of the light over any given portion of the sensor stays the same.

+NightHawkInLight I agree with you, sensor size doesn't change the final exposure, and yes the light intensity is the same, but if you hypothetically shrunk a FF to an APSC it will receive a more intense light for each mm2

Only if you also narrow the focus of the lens accordingly to match the shrunk sensor, otherwise it would be no different in exposure. That's how a speed booster works

Janet Crossland Thanks, Janet! It's my pleasure.

James Melito he’s proven it mani times on camera

@@sebastianmorales6849 if you'd measure the width of stuff in focus on sensor, using millimetres, it will be exactly the same for a crop lens and for a FF lens

Yuliya Brown f/2.8 lets in the same light per square mm regardless of the sensor size, but it doesn't let in the same total light. Total light is what determines total image noise and depth of field. Check sdp.io/crop for more info (as well as the following videos).

Tony Northrup I watched your videos. I got really confused, so I went and read up on all this at diff place. I found articles on this site (www.clarkvision.com/articles/does.pixel.size.matter/index.html) helpful to understand. I am not sure that I will agree with you on the total amount of light. The amount of light that lens lets in depends on the size of the hole. The amount of light the sensor can capture, depends on the sensor. so I think the lens lets in the same amount of light because the hole doesnt change, but the sensor with smaller pixes doesn't capture it all. So I came to conclusion that on the cropped sensor your best bet is to have as faster lens as possible. I am not sure how useful f1.4 on the full body, I think there will be hardly anything in focus, but on the cropped sensor you let in more light and hopefully will reduce the noise and your depth of field will be actually a little more useful than on a full frame. I am still trying to figure it all out. But thats why I am not crazy about sigma 18-35 f1.8 . I think the zoom range is not very useful for portraits, and you dont shoot landscapes at f1.8. so unless you constantly shoot large group of people in low light, I am not sure its worth all that excitement:-) I must be missing something, I am just way too new to all this:-)

Yuliya Brown Provided the lenses are optically perfect in terms of distortion, you can take the EXACT same image with a 14mm lens as with a 200mm lens, all you have to do is stand in the exact same spot, take the pictures and then heavily crop the 14mm image to match the 200mm image. I guarantee the exact same compression minus the depth of field due to the physical size of the aperture (matching DoF is when you need to move). So yes, a 50 can produce the exact same compression as an 85... Moving on... The f/1.4 aperture is useful on a full frame, low light, for example, or those artsy-fartsy bokeh-licious shots of food and things and YES, you most definitely can shoot landscapes at that f-stop. When things are far away (and obviously if you focus on those things), such as a mountain range, your dof gets REALLY long. If you don't have much going on in the foreground - there is no point in going at f/22 at all. I'm not saying f/1.4 will be sharp, I'd obviously go at f/4-f/8, but that's only for sharpness. Your mountain range would still be in focus. Another thing not to confuse over would be the physical size of 'the hole', the aperture. Although long lenses have massive apertures and wide lenses have tiny ones - the light gather is the same at the same f/stop. That's because the wider the angle of view - the more light can hit the front element, the more focused the beam of light is because of those bulbous elements. That's why we have this standard and that's why it works. Optics is an amazing little bugger that confuses a hell of a load of people, but it's not THAT hard to understand if you put your mind to it and TEST... :) If Tony Northrup has anything to add to or correct me with - feel free to do so!

I can see what you are saying Yuliya, but here it is as simply as I can put it. Two cameras, both 20 MP, one a full frame and one a crop. You put the same 100mm prime lens on both cameras and take a picture of a rectangle painted on a wall, both shots are taken from identical distance. The distance chosen is the distance at which the rectangle perfectly fills the frame on the crop sensor camera, we will call this distance A. On the full frame camera the field of view is wider so the rectangle would not fill the frame, even though the shots are taken from exactly the same distance. On the crop sensor camera you now have a picture of the rectangle at a resolution of 20MP. To fill the frame and get a 20MP image of the painted rectangle on the full frame camera you have to either a) move closer to the rectangle or b) stay where you are and put a 150mm lens on it. So, to sum up, yes, the lens used was a 100mm focal length lens and the lens itself stays 100mm focal length regardless of the camera it's on, however the image it produces on the crop sensor is EQUIVALENT to the image produced by a 150mm lens on a full frame, or, to get the same 20MP image of the rectangle on the full frame camera, you would need to use a 150mm focal length lens when taking the shot from distance A. Hope this helps : )

This is the biggest misinformation on the internet about focal lengths, dof, and all that. Yuliya you are 100% right and i have failed every time at getting people to understand this. Using an apsc sensor with say a 50mm lens is comparatively equivalent to a 1.6x magnification of the fov seen from a full frame 50mm shot. Optically nothing has changed, the vessel to capture the photo is still a 50mm lens. Ill make an analogy, lets say you have some bears to feed. You buy Kanon FF bear food which is made for Kanon FF bears which all weigh 160lbs. It says 'feed bear 50lbs daily'. Thats 32% of the bears body weight for a healthy bear. So then you have another bear you want to feed but its a smaller Kanon CF bear that only weighs 100lbs. You transfer over the same food but the bear gets much fatter, thats because what was 32% of the larger bears body weight is actually 50% of the smaller bears body weight. Then you say ' wow cool, how do i get the big bear to match the little bears fattness? So you then go back and calculate 50% of the Kanon FF bears body weight is equal to 80 lbs of food. Then you can make all kinds of converse associations including ' 50lbs of food on a smaller CF bear, is equivalent to 80lbs of food for the larger FF bear' OR 'if i like the figure of the FF bear when i feed him 50lbs a day, i can feed the CF bear about 31lbs of food a day to acheive the same result.' So YES 50mm on an apsc is equivalent to an 80mm on a full frame but, they are not the same bear! The bears are equally fat or fit but not the same!!!!

Sure thing!

1965ohio the crop sensor still has more pixels per inch, therefore with that denser pixel count the flaws in a lens become more obvious imagine if a 5ds mark 2 had a 61.44 mp sensor. The maths I did was 24mp x 1.6^2 the square accounts for the area of the sensor as they're two dimensional. The 5ds proved some older canon glass couldn't keep up a higher megapixel camera will do the same again

+Joe Addison "the crop sensor still has more pixels per inch" eeehhhh, by a little bit, doesn't make much difference between the 5DSR and the 7DII.

"If all these L lenses suck on APS-C, then they will all suck on the 50MP 5DSR." Nope. Hold your horses for a moment. They will look very similar in a 100% magnification viewing. But as the later is a crop and we need to scale both to a common display size to make the comparison. Think about it, it's like a literal crop, so take one image with a 5DSR, reframe so that when you take a second one, the crop of it has the same framing as the first image. Stretch out the later to fill the same area (or downsize the larger at your preference)... which do you expect is better?

Yes, cutting off the sides changes the apparent noise for the overall final image. The total light is the important determiner of photon shot noise, not the light/area (though indeed the light/area is the same, but not really in the final image once they are resized to a common viewing size, at which point light/area is more for the larger sensor).

Your comment makes no sense. They would produce same resolution if you cropped the 5DSR image. If you keep it as it is you get over twice the number of pixels in effective resolution. You do not seem to get the concept of the final image. The idea is not to view pixels in 1:1 size. Nobody says all L lenses suck on crop. The issue is that in some cases one might not get what one expects.

Sami Elias You're welcome, and thanks!

Thanks!

That's exactly my point. I also use a FF lens on a crop sensor and it's way better than my kit lens in terms of sharpness, plus it's an wide angle lens. I will eventually move to a full frame body so there's no reason to buy crop lens and sell it and get back a new one. Whereas I can only sell the body and keep all my lenses.

@Eternal Peace No problem. Glad I could help. Have fun taking pictures.

+Philip Bloom Have you ever notice how sexy your name is?

I’ll like to know too

Samtagri Man, I use that thing all the time. Some things, like wifi set up and quickly focusing on desired points, are night and day easier with the touch screen. Want to make sure the eyes are in focus... simply touch them and the camera focuses there and takes the shot.... too easy!

Samtagri Exactly.... I post a lot of stuff on the fly. If the shot needs little editing, I can edit in Snapseed or VSCO on my iPad and post from anywhere. That, and using my iPhone as a shutter release is legit.

singletrack29349 Yeah, where are our full frames with touch screens?! People always mock me for wanting touch screens, but that's cuz they aren't using them regularly like we do...

Tony Northrup I was actually really disappointed that the 6D didn't have one.

Samtagri The 7D doesn't have wifi cause the signal could not get through the weathersealed alloy body. Same reason all pro models don't have it. And it IS gimmicky in a pro camera. I'll give you the touchscreen, but wifi is for phones and instagram.

The focal length for example is a fixed measurement. It just behaves differently on different sensor sizes. Which is why the crop factor is used to transfer it into a 35 mm equivalent. You always have to keep in mind that it's just an equivalent to ease comparison between aps-c and ff sensors. I think the practical use for this 35 mm equivalent is getting less and less significant. If you know how a 35 mm lens 'behaves' on your aps-c sensor... you're good to go.

I don't think that's what he was saying, but that a lens designed for a FF sensor will yield a different field of view, related to the crop factor. A lens designed specifically for APSC should yield results true to its focal length. I'm not totally sold on the aperture crop argument but perhaps it's because I just don't know enough.

??

Great staff is that you also cut the corners (it's like zoomed already 1.6x) when you mount fx lens on a crop body. But loosing dept of field.. Crops are good nowadays and tele lens are very expensive so someone can benefit from it.. In other hand wide lenses are also pricy so anyone shooting wide should stick to full frame. Cheers

Dude... Seriously.. I was watching and then was like... Wait WTF?! Didn't he just say the exact opposite of this?! 🤔

I think Tony still believes that light exposure is converted for APS-C along with depth of field. That isn't the case, light per square mm is identical, and even if he's trying to use pixel density as some sort of measure of low-light performance, that went out the window with BSI sensors like the one on the D850.

Yeah, I like this guy but he gets several things wrong as can be expected by anyone who makes this many videos. Most people can figure out where he goes wrong. It's when he talks to the complete beginner when he probably is giving some costly advice. I'd suggest people don't rush into spending a bunch of money on equipment until they get some experience.

It’s because he is cropping away the extra pixels at the edges

@@gutenbird When I first got my camera(Canon T6i) a friend let me use a really expensive lens. He is a Pro photographer. The pics I was able to take with that lens on my cheap crop body were astonishing. The background was completely blown out, and my subject was tack sharp. And I have not been able to match that level of sharpness since with my kit lenses(18-55, 75-300). Tony says I can get sharper photos from the 18-55 kit lens, than I could with an expensive lens on my APS-C. I'm not sure why he would say that, but it's patently false. I have the images to prove it. Not sure about all of that math he does, but I'm not sure it applies to the light the same way it does to the focal length. But better glass is just that... better. No matter what size sensor you have.

we

+EvulDali i heard that using full frame lenses on crop sensor cameras can damage your sensor, is that true?

BigLou7711 No. That is not true.

+BigLou7711 No, using crop lenses on FF bodies can damage them*

+oliver24x No that is not true either. DX glass on FX body is harmless, there's just a few strange and fun image effects. *

+Art Altman True. That's why it doesn't matter that much if the lense is actually f/4.2, unless you care about the background blur. A 50mm f/1.8 will still be a really fast lens on an APS-C body. This can be tested easy with using the same lens on full frame and APC body, use the same setting and see that is exposed the same. Obiviously you will not get same field of view. A 50mm on FF will have 50mm fov, while on an APS-C it will have 75 (or 80 for canon).

+Art Altman Edit: P.S. in short: Higher Pixel-density requires the light to be even more focused in order to get the same signal strength (per pix) out of a physical smaller sensor. (same technology assumed). ... but leaving my ramblings from before in for reference. Hmm, does the following argument make sense ? The 2.8 on a FF lens is calculated with a 35mm sensor in mind. On a APS-C you use only the portion that is hitting the smaller sensor which is overall less then the amount hitting the FF. Or this Argument: Because a lens is designed to spread the light evenly over the sensors surface, it doesnt matter how big the sensor is. Every pixel get the same amount of light. Or lets rather say every square inch. The Problem beeing that an APS-C Pixel is much smaller in dimension then one Pixel of a FF sensor. This also means the light would need to be much more focused in order to get the same signal strength in the sensor readout to be equal to the readout of an FF chip. ... this obviously will not change when putting the same lens on different bodies. Come to think of it the second one is much more likely ;)

+Jens Vielmann "The 2.8 on a FF lens is calculated with a 35mm sensor in mind" No, because f-stop is the ratio of the aperture diameter to the focal length. The incidental light intensity at a given point, all else being equal (aperture, focal length, and transmittance) is the same regardless of the lens' intended image circle. The thing to keep in mind is that a FF lens of a given focal length will be physically larger than one intended for a smaller image circle, thus the physical aperture, in absolute diameter, will be larger. This is what accounts for the theoretical difference in total light per mm^s at the image plane: the larger lens admits more photons, in absolute value. APS-C lenses, conversely, have a smaller physical aperture. However, the ratio of that aperture, it's f-stop, still indicates the amount of light admitted relative to the intensity at the image plane. I routinely use medium format lenses adapted to smaller sensor areas, and the behaviour does not change. A 90mm Asahi 6x7 lens adapted down to EF and put on a 6D behaves just like you would expect a 90mm lens to behave. This is pretty easy to test just by putting a chart shot of the 90mm next to a chart shot using the kit 24-105mm L lens set to 90mm. At the same aperture you will see little more than slight exposure differences which are attributable to the transmittance of the lens itself.

+Daniel Nguyen "if a lens designed for crop sensor is f/1.8 would it produce the same amount of bokeh as a Full Frame lens on a crop body with the same focal length and aperture?" Yes. Regardless of intended format the bokeh will be (more or less) the same when the lenses are applied the same. A 50mm f/1.8 FF lens and a 50mm f/1.8 APS-C lens will produce nearly identical images when used on an APS-C sensor. There will be some differences, as there are between all lenses, but the depth of field, bokeh, field of view, and exposure value will not change.

+Folding Ideas If using a Canon 70D will a crop lens at f/4 produce the same amount of bokeh or depth of field as a full frame lens at f/4 at the same focal lengths? By same focal lengths, I understand that the full frame lens will be a larger focal length, so let's say the crop lens is at 50mm and the full frame lens is at 31.25mm (exact same focal lengths on both lenses).

That sounds funny! Dslrs upgraded from 8 to 10 megapixels or from 18 to 20 etc and DXO told you 2megapixels makes no difference... I doubt about their seriousness now!

the reason he multiplies the aperture by the crop factor is to get a similar depth of field but you are right, the exposure (or perceived brightness) is not to be multiplied by the crop factor it remains the same, but you must also multiply the iso by the crop factor squared to get a similar noise level (assuming they have a comparable pixel count because more precisely it is the ratio of individual pixel surface squared ).

hey schumifan78! of course, the f stop does not change. the maximum opening of the lens will be the same, never mind onto which body you mout it. BUT: if you mout a FF lens on a crop body, a lot of light goes not onto the sensor but "shines" next to the sensor, on that area where the rest of the FF sensor would be, if you had a FF sensor. so the ammount of light hitting the crop sensor is less than the ammout of light collected by a an aps-c sensor. that is the reason tony says that the maximum f stop is reduced. maybe he should have said "the ammount of light hitting the sensor is reduced on a crop body by the factor of the crop".

The exposure over the image circle doesn't change but all things being equal the crop sensor obviously captures less total light, right? That's in addition to the effects on field of view and depth of field. These people who confidently, even truculently say the aperture doesn't effectively change are nuts IMHO.

ONLY with FOV

This exact same topic is in every second comment on this video. Check sdp.io/crop

I use a full frame lens on a crop sensor, cause eventually I will move to a full frame camera. I can tell you that it works perfectly fine, the sharpness is way better than my kit lens and it's also wide angle.

This is true but I have no idea how it relates to the sensor size

Size always matters dude

CHRIS HENRY You're welcome, and thanks for your support!

+maghi “Magi” cat If you want more information about perceptual megapixels, here ya go: kzfaq.info/get/bejne/g7iqgrGK0tCsY4E.html As I mentioned in the video, I used DxOMark as an objective source, however, the root of this comes from actual experimentation and the frustration of many, many photographers who've contacted me because they were getting unsharp results with full frame lenses on crop bodies. I believe I explained why the scenario works differently for wildlife; you have to crop anyway, and the higher pixel density helps extract more detail from the lens. It doesn't help as much as getting closer and using the full sensor; if you didn't have to crop, you'd get better results with the full-frame body.

Buy twice??

@@aight365 I think he means you have to change from dx lens to fx lens if you change to full frame

Be nicer to people. We're all just doing our best.

Aidan S please suggest me some best lenses for cannon 800d

s k Some really good lenses I recommend: 10-22mm, 50mm and 55-250mm

Depends on the camera brand. Sony, Canon, Nikon? Which one?

Fugi 50-140 f2.8, really it'd have to be f 2 but that doesn't exist, so it's this lens

No. This adds to my photography and helps me enjoy it more.

Tony Montana Thanks!

+Roxy-Jane Stone Right, obviously crop factor is a mathematical conversion and it doesn't alter physical objects when you decide to use it, just like converting miles per hour to miles per kilometer doesn't make you go any faster. Nonetheless it's useful for understanding the results you get with your gear. If you or someone else reading this is interested in learning more, visit sdp.io/crop.

very true, well explained, not misleading.

so regarding light 2.8 is 2.8 on FF as well as Crop sensor and regarding DOF it is 2.8 x 1.6 (on canon crop sensor), correct ?

Well despite what Tony says I agree with Roxy… And anyway if there is any difference between full frame and Crop sensor it's as Zack Arias said : NEGLIGEABLE! kzfaq.info/get/bejne/hq6JnMeWz7qXe40.html Same no sens with pixels war. kzfaq.info/get/bejne/iqx0g7aB05fekpc.html

Miles per hour to kilometer per hour… Not sure you understand fully what you're stating...

I'm afraid you are incorrect sir. It is exactly as Tony says in this video. I have tried it for myself. I used the same 24-70 2.8 lens on both a 6D and 60D. I shot the same scene, at about 44mm & f4.5 on the 6D and 70mm & f2.8 on the 60D and the 2 images are IDENTICAL. They are totally indistinguishable. Try it for yourself.

+Charles Ingraham Photography You shot: 44mm on a full frame, and then 70mm on a cropped sensor... therefor the equivalent would be on the 60D which would equal 112mm lens... so how is a 44mm lens and a 112mm (equivalent) the EXACT same shot? I think your math is off... Crop sensors make you already long lens even longer.

+Charles J Gartner I apologize. I shot the 70mm @ 4.5 on the full frame and approximately 44mm @ 2.8 on the crop.

+Charles Ingraham Photography my only point is: When you get closer to a subject you get shallower DOF... When you stop down, you get shallower DOF... the sensor size does not matter, unless you start compensating for those factors by moving closer or switching lenses. .... a lens does not know or care what your sensor size is.

+Charles J Gartner You must be making a different argument from what Tony is even talking about. The lens "behaves" differently on different sized sensors. That goes for both the focal length and the depth of field. That's a fact. I beg you to try it for yourself. Photograph the same scene from the same position using a full frame camera and a crop camera. Use the same zoom lens, and use the equivalent focal length and Aperature from full frame to crop and you will get IDENTICAL images. He is simply correct about this.

Anne Hodermi Search my channel for 'crop factor' for 3 videos covering why you should multiply the aperture by the crop factor any time you multiply the focal length by the crop factor. Re: megapixels, lots of people need more detail, not just professionals. People do crop, especially for wildlife, and many people make large prints. If you don't need it, that's fine. But regardless, if you didn't need the extra detail, you probably don't need to be buying the more expensive full-frame glass, either. My only goal is to allow people to make educated buying choices.

Tony Northrup Ok with you concerning megapixel for crop and large printing but I think people who need this don't need your advices (they already know, as they know the difference between sharpness and definition). For crop factor (of aperture) I will try it another way. A body is a body. A lens is a lens. Aperture is a physical parameter of a lens. I know that the result is different (bokeh) depending on sensor size. But the lenses doesn't change because you change the body. The 50 mm f/1.8 on my old F801 is a 50 mm f/1.8 on my D300. This lens has been design before digital camera even existed, for 24x36 film. Because of the APS-C sensor size, angle of view is equivalent to à 75mm. This is not a conversion but a value to make people understand what kind of view they will have. You don't convert anything. I also have a 18-200mm (f/3.5-5.6) on my D300. If I zoom it to 50 mm I have the same view as with my fix 50mm. Of course I will have max aperture of around f/4.5 on the zoom. But on the fix 50mm, believe me, it is a f/1.8. As you see in this last paragraph I didn't convert anything ;-) You probably should do so to avoid misleading people. (Giving equivalent focal length IS NOT converting, it just help to compare angle of view on different body).

+Ian R This can help: kzfaq.info/get/bejne/g7iqgrGK0tCsY4E.html

Bring this comment to the top people ! As DXO mark does seem far from flawless

HA! With a divining rod or a Ouija board.

hmmm I would progressively shrink then expand the image by slowly increasing factors until the reconstituted image looks softer than the starting image. e.g. if you shrink a 6000x4000 image to 3000x2000 then expand it back again, and it looks identical to how it started, then the perceptual resolution of the starting image was no greater than 3000x2000

+harut82 I've researched compression and experimented with it, and it seems to be a factor of only the effective focal length. If you can find a photographic example showing how compression is a factor of sensor size but not effective focal length, please send it to me (tony@northrup.org).

I'm not arguing that compression is a factor of sensor size. I'm arguing that compression is a factor of "focal length" not "effective focal length" I'm arguing that compression of a 50mm lens is always the same no matter what the sensor size is behind the camera. If compression doesn't change when you crop a photo in lightroom why should it change if using a crop sensor?

35mm on crop body will not behave like a 52.5mm on full frame. The field of view will be the same, But on the crop body with 35mm lens you'll have the compression of a 35mm lens while on the full frame body you'll have the compression of a 52.5mm lens.

facebook.com/IFLphotos/posts/1309117285769267

+harut82 That article doesn't compare different sensor sizes. Seriously, an equivalent 50mm has the same compression, regardless of sensor size or absolute mm.

yikes

+Alberts Kuks Please see sdp.io/crop for detailed information about this. Obviously, you're right that the camera settings don't change--but the total amount of light the sensor is getting is very different.

+Tony Northrup _"Obviously, you're right that the camera settings don't change--but the total amount of light the sensor is getting is very different."_ But you neglect that the total light per square mm is exactly the same. The perceptual changes exist only because you have to stand back from your subject by the crop factor to get the same FOV as FF. Light intensity is the same for any given Fstop from any given lens no matter the size of the sensor, the aperture variable isn't real, it's derived from the focal distance to achieve the same FOV. Now here's something you might not have considered, if you take a picture with the D7000 and the D810 at the same distance from the subject and all else equal, your depth of field, your aperture, your focal distance and bokeh will be exactly the same. the only difference will be the framing, the field of view. So when you talk about these settings changing, they are not, they are exactly the same, the variable comes in when you want to frame the shot the same, your relative distance from the subject moves back by a factor of 1.5x, this is what makes the perception changes from crop sensor to full frame. Your depth of field at the different focal distance is what has changed, not your aperture, because the exact same amount of light per square millimetre falls onto the sensor. Your focal length changes, not because of the lens, but because of the size of the sensor and its relation to the circle of illumination. Your reliance on the perceptual mega pixels as a measure of the actual lens performance is flawed. Let me prove it. The D810 36 MP 24 x 36mm FF sensor The D7000 16.3mp 15.6 X 23.6 Crop sensor The D5300 24MP 15.6 X 23.6 Crop sensor Lens Nikon AF-S Nikkor 50mm f/1.4G Pixel area D810 23.72um squared D7000 22.75 um squared D5300 15.13 um squared DXO sharpness D810 21 MP D7000 10MP D5300 14MP Relative percentage D810 21/36 = 58.33% of perfect D7000 10/16.3 = 61.35% of perfect D5300 14/24 = 58.33% of perfect Perceptual megapixels are a guide, nothing more they are actually measuring sensor performance to pixel density rather than the lens itself. Just look at the different scores of the lens from the D3200, 5200, 5300, the only difference is the sensor, not size or pixel density (minimal) yet there is 3 perceptual megapixels difference between them (12, 11, and 14 respectively) One thing you forget about crop factor lenses is that because of their smaller circle of illumination, vignetting, barrel distortion, focus and CA at edges are more pronounced than using a FF lens, because you are only using the centre 67% of the FF lens on a crop sensor. They don't just cut out the centre of a FF lens to make the crop lens version, they design them within acceptable limits.

chuck90504 I would suggest that you rethink how you are actually considering the image circle and what the actual sensor is doing. For any given circle of illuminations image, nothing changes just because you are using a different size sensor. How much information from that circle of illumination you get is what changes. The only variable that the sensor does is that it is a crop of the available information. Which is why I used the D7000 vs the D810 sensors as the pixel density is near identical and so does not get the effects relating to the circle of confusion of the DOF as a variable of pixel area. The whole DOF arguments relate to framing, to frame on a crop sensor the same as on a FF sensor is to move back the corresponding distance to the subject by the crop factor ratio. This focal distance change is what effects the DOF for any given lens. This can be proven by taking a photo with the same lens at the same distance from the subject so that the focal distance is the same for both shots and crop the FF D810 to the D7000 crop area in post production. Of course you cannot crop the other way around, so you need to move back 1.5x the distance from the subject with a D7000 to achieve the same framing as the D810, and as soon as you do that then everything else changes with it including DOF.

chuck90504 _"When you have to bring in movement to achieve the same look, you've got an issue with perspective distortion"_ You get that using a different lens anyway. A 75mm lens on a FF is a 50mm lens on a crop. Given that f2 is different on both lenses (50mm 25mm aperture and 75mm is a 37.5mm arpeture) , you get a different perspective anyway. Much is explained from a relative perspective of the different formats, most explanations use framing relative to a FF sensor and from that we get the variations in DOF and perspective, because with the same lens, the FOV of a crop sensor is the same as a longer lens on FF. But given the equivalent lens, the f2 while still f2 and 50 mm on either camera, due to framing the f2 becomes f3 on a crop for DOF comparisons, which is kinda bullshit because it doesn't affect light intensity, because when you frame with that lens you are standing back 50% further from your subject, but still at f2. It is the distance to subject that is the variable here, the Fstop recalculation is just a virtualization of the actual. Consider the minimum focus distance of a lens, in both cases let's say it's 1 metre, the crop sensor while not actually allowing you to get closer to your subject, will in effect magnify the frame compared to a FF sensor. Where you would crop a FF at minimum focal distance for a small subject, the crop sensor appears 1.5x closer as it's already cropped. Higher pixel densities means more detail on a crop sensor generally, exceptions being the D7000 vs the D810, where the crop and the FF have the same amount of detail in terms of number of pixels of the subject at minimum focus distance. On both the same lens and the same F stop produce the same results.

chuck90504 _"if you and I both shoot a 100mm lens and I'm standing 1.5x closer than you, 9 times out of 10, I'm going to get more detail."_ That is going to depend on the ability of the lens to resolve to the pixel density. _"it's pretty obvious that a simple concept of distance continues to escape you. "_ *"It is the distance to subject that is the variable here"* Distance to the subject is the very basis of everything I've been saying. The change in FOV has nothing to do with the lens, as it is still producing the same circle of illumination, but a crop sensor can only gather a percentage of that FOV hence the equivalent is translated to the lens in the calculations, though the lens has nothing to do with the actual changes. For the sensor to get the same framing from it's limited FOV, the crop factor tells us the distance change. The way explanations revolve around lenses is a smoke and mirrors explanation that works, the actual explanation lies in the percentage of the circle of illumination that a crop sensor can see along the vertical and horizontal planes. The only advantage of a crop sensor, is that more often than not it has a higher pixel density, therefore it translates the analogue information from the circle of illumination at a higher megapixel count, but with the loss of light intensity per pixel, because of the smaller pixel area, but not per square mm of sensor. Full frame sensors are better in low light, not because of the sensor size, but the area of the individual pixels. _"Even in those specialized genres, the advantage of crop is not evident until you've exhausted your longest lenses. "_ The length of the lens isn't the critical factor, it's minimum focal distance that is. What happens when you use macro tubes, you're closest focus shrinks in distance.

Detail is not sharpness? It's both resolution and sharpness, if your lens isn't sharp it's going to take "blurry" pictures and while you have a high resolution you have way less detail. And the higher the resolution the more detail is possible with a sharp lens.

Tony has said many times that dxomark doesn't tell the whole story. He is using it here to get the information necessary to make his points. It seems you are quibbling over semantics as well. If you would look at some of the other videos that go over these technical details you would look past whatever small ambiguity in words used and understand what Tony is saying better here. I don't feel sorry for his wife or anyone else that gets to listen to someone that not only knows his subject but can explain it so clearly and with a pleasant voice and mannerisms. Honestly, I can't think of anyone doing a better job for free on the internet yet you need to criticize him on a video that nearly everyone would agree is very good to excellent. Methinks the problem is with you and not with Tony. I'm not saying this as an insult. I wish you the best and happy holidays, sincerely.

Galactu5 what problem are you talking about, I have no problem with Tony or his videos, i am a subscriber to his channel, and I understand all he is saying in this video, but that doesn't mean I have to agree with everything he says, and I have the right to give my opinion in return, and do you not see that what I said about his wife was just a joke, anyway happy holidays to you also, I hope Santa brings you a new camera

photographerjonathan hello! You mention a few times that Tony is overly technical. That is the main problem I see in your comments and I find that opinion to be inaccurate. I'm aware you like Tony overall, but the fact remains that photography has technical aspects to it and it is nice that someone out there has a channel that explains the commonly asked questions and the minutiae with such clarity. It may seem overly technical to you, but Tony's explanations and formula empower us to understand the concepts rather than just have some rough familiarity. You mention you understand what he is saying here and elsewhere yet see it as overly technical. That is the main problem I was getting at and I just wanted to suggest that it didn't seem to mirror reality. Wish you nothing but the best and may you get that lens you have always desired this holiday season! Thanks for not taking my comments as an attack and for not attacking me back which is sadly way too common. Peace!

photographerjonathan Them 'numbers' may be for mathematical engineers, but believe it, when you're on a professional commercial shoot - no amount of 'creative' will make up for noisy images in the eyes of the director/client...

Chase Martin Thanks, Chase!

@@TonyAndChelsea this seems like advice that was good, but had long outlived it's usefulness. My 10d and bodies from a couple decades ago benefited more from the fancy glass as they weren't able to out resolve the lenses.

John Gardiner he never claims a „loss of light“

You are right, it only effects the Depth of Field, not the total gathered light.

Exactly, the total light gathered DOES not change, but the DOF does.

I get your point but why there's a noise difference?

+THEKMT6 The light falls on a smaller surface so there will be less light gathered in total. To have the same exposure as on a full frame sensor, the sensitivity of the sensor must be higher, wich brings more noise.

Vincent van der Pas Well said, sensor size determines Equivalent values of Aperture, focal length and iso Regardless of the ino displayed in camera.

THANK YOU. At last, someone spoke the truth.

Exactly, Photons don't change resolution because they are falling on a "smaller" sensor ! They don't make lens glass according to the sensor resolution. Quality may be but not resolution...

Not to mention that I can put my 70-200 2.8 on my full frame and crop body and both cameras meter the exact same exposure. If the crop body wasn't getting the same amount of light, then the exposure would change. Period.

What?? YOU are the one who is confused. Wow, lol.

Hi im just a newbie i bought a sigma 105mm f2.8. dg os hsm macro lens but my cam is 80d apsc will i get any problem on sharpness for macro shots since the lens is intended for full frame cam pls advise me thanks

Thanks man to assure me. I was confused to know FE 28mm f2 lens will be f3.5 lens on my A6000. But he is wrong here I guess. My intuition also says so.

You are wrong, I have done tests myself and he is correct that full frame lens is sharper on full frame than on crop camera because the full frame camera has bigger pixels. I have never seen one case of a full frame lens being sharper on a crop frame camera.