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adam

05-05-2009, 03:55 PM

I'm curious about the advantages of shooting full-frame versus shooting crop. I've read various assertations that switching from a 40D to a 5D is like upgrading all of your glass, that a crop body gives you extra "reach" when using telephoto lenses, that you'd get similar quality shooting with a crop body as you would shooting full-frame and croping in post, and that the real image quality difference in full-frame comes when you shoot at high ISOs. So which, if any, is it?

I'm pondering what I'm saving my money up for...not in the immediate future, but probably a few months down the road. Among other things, I do a lot of airplane photography...say I took a picture of a plane with a 300mm lens and the plane filled the frame on my 40D. Now, say I took a picture of the same plane with the same lens at the same distance with a 5D and cropped it in Camera Raw such that the plane filled the frame. Which picture would be sharper?

(I don't shoot at high ISOs, but I do quite a bit of landscape/cityscape shooting where the more detail the better, so I'm already fairly certain a full-frame body would make that look nicer.)

Colin

05-05-2009, 04:18 PM

With a full frame, you can use the entire full size lens, collect more light, and any errors in the optics will be relatively smaller in proportion to your image. You also get a more shallow depth of field with a given lens aperture, because the wider angle of view means that you can get closer.

A crop body focuses your pixels in a smaller area. it effectively crops the image for you, so you don't waste your pixels if you would have cropped anyway.

A crop body has an advantage if you arelikely to crop anyway (telephoto/macro), and you can then use the EF-S line of lenses as well.

However, if you have the glass for it (and don't mind carrying it) I'd lean towards a full frame.

If you can get a full frame body with pixel density the same as the crop body, the only advantage of the crop body would be smaller file sizes. Technically, ignoring a host of other parameters, the crop body and the cropped full frame body would have identical resolution with the same lens.

Daniel Browning

05-05-2009, 04:30 PM

I've read various assertations that switching from a 40D to a 5D is like upgrading all of your glass,

Correct. All EF lenses have MTF curves optimized for full frame, so there is higher contrast and sharpness for a given print size.

That a crop body gives you extra "reach" when using telephoto lenses

True.

that you'd get similar quality shooting with a crop body as you would shooting full-frame and croping in post

That's only true if the FF body has the same pixel size. For example it's true when comparing the 5D2 and 20D: both have the same reach because they have the same pixel size. But the 50D is far superior to the 5D2 for reach.

and that the real image quality difference in full-frame comes when you shoot at high ISOs.

High ISO is one of the biggest, most important reasons to shoot full frame (and is one of the principle reasons that I do), but it's certainly not the only reason. Even at low ISO there are differences, such as higher dynamic range and better contrast.

say I took a picture of a plane with a 300mm lens and the plane filled the frame on my 40D. Now, say I took a picture of the same plane with the same lens at the same distance with a 5D and cropped it in Camera Raw such that the plane filled the frame. Which picture would be sharper?

The 40D would be sharper by far. The 50D would be better still.

(I don't shoot at high ISOs, but I do quite a bit of landscape/cityscape shooting where the more detail the better, so I'm already fairly certain a full-frame body would make that look nicer.)

Yes it would.

I'm curious about the advantages of shooting full-frame versus shooting crop.

There is a huge price premium to pay for a full frame sensor.

In new cameras, the 50D and 5D2 are similar enough to compare for this purpose (although the 50D has better autofocus, gapless microlenses, and an all new sensor with gapless microlenses instead of a copy of an older sensor with a few CFA changes).

The build and features of the 5D1 are similar to the old 20D.

20D used: ~$300
50D: $1200
5D1 refurb: $1400
5D2: $2700

$2700 - 1200 = 1500. There is a $1,500 price premium just for the sensor size alone. If you compare the 5D1 to the 20D, the premium is closer to $900. In other words, if you didn't really need the sensor size, you could save $900 and just buy a 20D.

Is sensor size really worth that much to you?

The answer depends on your need for the benefits that go along with full frame:

The big three, IMHO, are:

* Lens availability.
* Control over depth of field.
* Increased light gathering power.

For example, there are no wide angle primes for APS-C (EF-S), but there are dozens available on full frame. The 14mm f/2.8 on full frame would be most similar to a 9mm f/1.8 on APS-C, but there is no such lens for APS-C. The 24mm f/1.4 would be similar to a 15mm f/0.9 on APS-C, but again no such lens exists. The widest prime built for APS-C is the Sigma 30mm f/1.4, which is equivalent to a 50mm f/2.2 on full frame.

By "equivalent", I mean they would have the same field of view, same depth of field, same diffraction, and same light gathering power (light intensity times total area).

To me, those are the main benefits, but there are more:

Larger viewfinder.
Using EF lenses as designed (e.g. 17-40 becomes a "super wide angle" instead of a "normal")
Higher contrast from EF lenses.
Higher resolution from EF lenses.
Higher dynamic range.
Lower noise, especially shadow noise.
Better low light capability.

If you upgrade to full frame, but you can't afford a lens that is long enough, and you have to crop the sensor down to APS-C size anyway, then you've effectively thrown away all that sensor you paid for.

For example, 200mm f/2.8 on APS-C is similar to 300mm f/4.5 on FF.The 55-250mm f/4-5.6 IS is equivalent to a 100-400 f/6.4-9.0 on FF, but the 100-400 we do have has much wider aperture than that.

So if there is a longer, slower lens available for full frame, with similar autofocus capability, then you can upgrade and still get similar photos. But Canon often does not make a longer, slower version of the lens we're using on APS-C, and if they did, it wouldn't autofocus.

The only time you will get a benifit from full frame is if you actually *use* the full frame, which rules out cropping. For that reason, the 50D is the best choice for airplane photography on a limited budget.

Colin

05-05-2009, 05:19 PM

Err... I meant what Daniel said... [:)]

Tom Alicoate

05-05-2009, 05:24 PM

That was a lot of great advice. One other benefit to Full frame is that of diffraction. It is a little complicated and I am not the person to explain it, but diffraction for landscapes where you want to get a large amount of the photo in focus can be difficult with an APS-C sensor without also getting some of the blur associated with diffraction.

I have thought about this long and hard too. I have almost decided that instead of the 5DMKII, I will go with the 60D whenever that comes out. I want thelower noiseof the Full frame, but I can't loose the higher pixel density provided by the XXD series. I can't afforda lens longer than 400mm, and a high quality photograph with a littlewolf is not nearly as desireable to me as a larger wolf with a little bit of noise.

Of course in a perfect world I would have the funds for a 5DMKII for portraits and Landscapes, and an XXD for nature and aviation photos. [:)]

Tom

Daniel Browning

05-05-2009, 06:36 PM

Thanks for the post, Tom. I too would prefer a detailed, but noisy wolf. I have a comment about one thing, though:

One other benefit to Full frame is that of diffraction. It is a little complicated and I am not the person to explain it, but diffraction for landscapes where you want to get a large amount of the photo in focus can be difficult with an APS-C sensor without also getting some of the blur associated with diffraction.

That idea is believed by many respected photographers and is a widely held position on many forums, web sites, and magazines. You are in good company. However, it's actually a misconception.

The reality is that diffraction is the same for all cameras, no matter the sensor size, because it scales in perfect proportion with depth of field.

For example, let's assume a 30x20 print size viewed at a close distance with a high acuity. If made from a full frame camera at f/22, it will have reduced contrast caused by diffraction. To get the same depth of field on APS-C, one needs to only stop down to f/14. Stopping down to f/22 would cause the APS-C to have *deeper* depth of field than the full frame camera, and that is not necessary, desirable, nor comparable. Instead, it should have the same iris diameter (focal length divided by f-number) in order to have the same angle of view, perspective, and depth of field.

The same 30x20 print made from an APS-C camera at f/22 will have *much* worse diffraction softening. So on the face of it, one might draw the incorrect conclusion that full frame has an advantage with regards to diffraction. But it doesn't, because the APS-C doesn't *need* to stop down to f/22 in order to get the same depth of field.

The diffraction is the exact same on both. It scales to all sensor sizes. On an 6x9 medium format camera (84x54mm), f/22 causes much less diffraction bluring, but the depth of field is much thinner than on 35mm. To get the same depth of field, one must stop down the 6x9 lens to f/51, but then the diffraction is back to being the same.

It goes in the other direction, too. A digicam (9x6mm) only requires f/5.6 to get the same deep depth of field as f/22 on full frame. And diffraction, too, is the same on a digicam at f/5.6 as it is at f/22 on FF35.

Essentially, diffraction and depth of field are the same on all cameras of all sensor sizes. The only difference is that larger sensors may have the *option* of using thinner DOF (and the reduced diffraction that goes with thinner DOF). If the large formats are used at the same DOF, then diffraction too is the same. Other things scale with DOF as well, including low light capability.

In short: diffraction scales with DOF, no matter the sensor size.

Jon Ruyle

05-05-2009, 06:47 PM

that you'd get similar quality shooting with a crop body as you would shooting full-frame and croping in post

That's only true if the FF body has the same pixel size.

It's also true if something other than pixel density is the limiting factor in image quality.

Tom Alicoate

05-05-2009, 09:52 PM

Daniel,
Yep, thats why I didn't pretend to know anything about diffraction. It looks like I need to get my photo books out again. I was confused by some of the talk when the 50D came out, around seeing diffraction when stopping down.This was not due to the sensor size it was due to the decreased pixel size and I forgot about that. It is in fact good news that an APS-C camera can get the same DOF as a FFwithout stopping down as much. In fact one of the things I have noticed with my lenses is that there is anoticeable increase in sharpness closer to the sweet spot of the lens.For landscapes I am actually better off trading in some of that DOF for increased sharpness by opening things up a little, say to f8, orf11, rather than f22 or higher. I have not completely thought through this idea yet so I will pose it as a question. Does this mean that if DOF is a goal, and keeping a lens close to its sweetspot is a goal, than a APS-C sensor actually has some advantage here?

Thanks for an interesting thread!

Tom

ShutterbugJohan

05-05-2009, 10:17 PM

If made from a full frame camera at f/22, it will have reduced contrast caused by diffraction. To get the same depth of field on APS-C, one needs to only stop down to f/14. Stopping down to f/22 would cause the APS-C to have *deeper* depth of field than the full frame camera, and that is not necessary, desirable, nor comparable.

What? I would think that it would be the opposite.

For example, assuming we use the 5D1 and 50D as examples; the 50D would have to have the aperture stopped down much farther than the 5D1 would for the same depth-of-field*, because the circle of confusion changes, and the 5D1 would render as sharp somthing that the 50D, with it's higher pixel density would render out-of-focus. Right?

Instead, it should have the same iris diameter (focal length divided by f-number) in order to have the same angle of view, perspective, and depth of field.

I understand all those terms, but not that statement; would you mind explaining what you mean a little more simply?

Thanks!

--Johan

* At least at the pixel level; maybe it would be different at equal print/output sizes?

Chuck Lee

05-05-2009, 10:36 PM

adam,

This article is why I purchased a used 5D even though I have a 40D. http://www.kenrockwell.com/tech/full-frame-advantage.htm ("http://www.kenrockwell.com/tech/full-frame-advantage.htm)

Headdresses quite a few assumptions.

Good read,

Chuck

Jon Ruyle

05-05-2009, 10:42 PM

Does this mean that if DOF is a goal, and keeping a lens close to its sweetspot is a goal, than a APS-C sensor actually has some advantage here?

I'm sure Daniel will have a more authoratitative answer, but my guess is the reason for the percieved "sweet spot" is that diffraction has not yet set in in. If this is true, then the answer would be no.

Dallasphotog

05-05-2009, 10:50 PM

Daniel Browning

05-06-2009, 12:03 AM

It's also true if something other than pixel density is the limiting factor in image quality.

You're right; thanks for the correction.

I was confused by some of the talk when the 50D came out, around seeing diffraction when stopping down. This was not due to the sensor size it was due to the decreased pixel size and I forgot about that.

Yeah, pixel size is a whole new (and big) topic. :) Under ideal circumstances (no diffraction, perfect focus, no motion blur, etc.), the 50D will have 21% higher resolution than the 40D. Under no circumstances will the 50D ever have *less* resolution; however, in the very worst circumstances (f/45 diffraction, focus way off, severe motion blur, etc.) the increase in resolution will be vanishingly small (0.1%). Every photograph will be between 0.1% better and 21% better. For most people, I think it will be much closer to 21%.

It is in fact good news that an APS-C camera can get the same DOF as a FF without stopping down as much.

I don't subscribe to that idea, personally. The way I see it, there is no advantage to either; they are just equal.

In fact one of the things I have noticed with my lenses is that there is a noticeable increase in sharpness closer to the sweet spot of the lens. For landscapes I am actually better off trading in some of that DOF for increased sharpness by opening things up a little, say to f8, or f11, rather than f22 or higher.

Yes, that is because the effect of diffraction is reduced.

I have not completely thought through this idea yet so I will pose it as a question. Does this mean that if DOF is a goal, and keeping a lens close to its sweetspot is a goal, than a APS-C sensor actually has some advantage here?

I think it's actually a disadvantage. Generally speaking, I think it could be said that the sweet spot varies by format size. One example might be:

4/3rds: f/4
APS-C: f/5
FF35: f/8
6x9: f/18

So if an FF35 lens has aberrations at f/5, but becomes diffraction limited at f/8, that's great for FF35 cameras. But when you put that lens on an APS-C camera, you get aberrations at f/5 or too much diffraction at f/8.

This is a natural consequence of the fact that we have so many decades of lens development for FF35, but only a few lenses built specifically for APS-C only. In cases where there is a lens built specifically for APS-C, it usually tromps the equivalent EF lens (e.g. EF-S 17-55 vs. EF 17-40; EF-S 60mm f/2.8 macro vs EF 50mm f/2.5 macro).

The lenses we do have for APS-C (EF-S) must have aberrations corrected at a higher spatial frequency and a wider f-number than equivalent EF lenses in order to have the same image quality.

One way to think of it is like this: the crop factor must apply to the *MTF chart* as well as focal length and f-number; otherwise the image quality will not be as good as FF35.

Thanks for an interesting thread!

You're very welcome.

I would think...

Thanks for the response, Johan.

For example, assuming we use the 5D1 and 50D as examples; the 50D would have to have the aperture stopped down much farther than the 5D1 would for the same depth-of-field*,

[* At least at the pixel level; maybe it would be different at equal print/output sizes?]

I kindly think you are mistaken, pixel level or not. To get the same angle of view, the focal length must be different between the 50D and 5D1. With a longer focal length and the same f-number, the 5D1 would have a wider iris diameter, which changes the geometry between subject and focal plane to change, which changes depth of field. However, if the f-number is 1.6X narrower, then the iris diameter returns to the same size as the 50D, and the geometric relationship between the subject, iris, and focal plane are again the same, so depth of field is the same. I think you'll find that DOF calculators and other resources will reinforce what I'm saying.

You do bring up an important factor, though, which is the effect of resolution. The 5D1 and 50D only differ in resolution by 2.2 megapixels, which is not enough to have a big effect on depth of field; however, there are times when total resolution can, indeed, affect depth of field.

If the 5D2 at f/9 is compared with the 40D at 5.6, for example, both will have the same depth of field at normal print sizes. However, at very large print sizes, where the 5D2's immense resolution can be utilized, it's possible that the DOF will be thinner. This would require the resolution to be preserved from the lens (aberrations, motion blur, etc.) through processing and display (e.g. 30x20 print size). Of course, if the thinner DOF is not desirable, it's always possible to just blur the 5D2 image so that it only has 10 MP of resolution, and then the DOF will be the same as the 40D again.

Basically, DOF will be affected by anything that affects total resolution; not in absolute terms, but relative to the viewer's acceptibly sharp CoC.

While I'm on a tangent, I might as well discuss reproduction magnification. To make a 12x18 print, the full frame sensor is enlarged by a factor of 12.7x. To make the same size print, an APS-C sensor must be enlarged by 20.3x. It is magnified much more because it is smaller. Notice that the difference between the two is the same as the crop factor (1.6X). It is that reproduction magnification that causes f-number to scale with sensor size for depth of field, diffraction, and a variety of other things.

Daniel Browning said: Instead, it should have the same iris diameter
(focal length divided by f-number) in order to have the same angle of
view, perspective, and depth of field.

I understand all those terms, but not that statement; would you mind explaining what you mean a little more simply?

It's my pleasure.

For other readers, let me prefix the explanation by saying that iris diameter means the same thing as pupil opening, physical aperture, absolute opening, "hole in space", and other similar synonyms. It does not mean f-number (which is "relative" aperture). The iris diameter is the focal length divided by f-number. For example, 50mm f/1.2 has an iris diameter of 41.7mm (50/1.2=41.7).

Let me try phrasing it in two additional ways:

For a given field of view, focus distance, and bellows factor, the lens with the widest iris diameter will project the thinnest DOF, no matter what the focal length, f-number, or sensor size.
Similarly, if any two lenses have the same iris diameter, the DOF will be the same, no matter what the focal length, f-number, or sensor size. Given the same field of view, focus distance, and bellows factor.

The iris diameter of 50mm f/2.8 is 18mm. The iris diameter of 80mm f/4.5 is 18mm. When 50mm f/2.8 on APS-C is compared with 80mm f/4.5 on FF35, one finds that they have the exact same perspective, angle of view, depth of field, and diffraction.

In short: Apply the crop factor to f-number and everything evens out.

This article is why I purchased a used 5D even though I have a 40D. http://www.kenrockwell.com/tech/full-frame-advantage.htm

He addresses quite a few assumptions.

Ken's site has some good content, but it's mixed in with a lot of misinformation, myths, and misconceptions. I did a quick review of that article; please oblige a brief response to a few of his points:

Bigger pixels collect more light (photons). More photons means more clean image compared to the relatively constant amount of electrons making noise. (Yes, I'm simplifying, but it's why bigger sensors are quieter and cleaner.)

Fatter pixels catch more light, so the larger camera doesn't have to amplify them so much for the same ISO sensitivity. This means that even though we wind up with the same exposure, noise and crud aren't amplified as much, leaving us with a much cleaner images without having to cheat with wimpy noise reduction filtration. There is simply less noise.

This is a myth that I busted on April 25th:

Myth busted: smaller pixels have more noise, less dynamic range ("http://community.the-digital-picture.com/forums/t/1055.aspx)

...all cameras smooth over the noise in flat areas to varying amounts where it's most visible...

That's only true for JPEG images, not raw.

the larger format camera sees the subtle difference between the white window frames and the light tan house

This is due to the difference in the spectral response of the color filter array and the JPEG processing, not anything caused by the format size difference.

Aside from those three myths, the information appears to be correct.

Thanks for the discussion, everyone.

Keith B

05-06-2009, 12:11 AM

I'll just add a simple note. I loved my EF24-70 F/2.8L USM on the 1DMKII, but I LOVE it on the 5DMKII. The extra bit of wide angle and the additional creative possibilities are pretty dramatic. If you came from film, it's going to remind you why you loved your wide angle lenses.

I own a 24 1.4 L prime that is a great lens. It was on my 40D 90% of the time. It was essentially a 38mm loved it but it wasn't quite wide enough all the time. So I figured it was time to go full frame (enter 5D mk2) and started shooting 24 and it seemed either too wide or not wide enough. So I finally ponied up and bought the 16-35 2.8L II and man have I found my spot(s). Between this lens and the 5Dmk2 my photography has become what I had always wanted it to.

The 16-35 is the best, most pratical (for me) and fun lens I have ever owned. The wide with a well thought out Deutsch Angle and images become so dramatic.

I LOVE this lens and FF.

Chuck Lee

05-06-2009, 01:43 AM

This article is why I purchased a used 5D even though I have a 40D. http://www.kenrockwell.com/tech/full-frame-advantage.htm

He addresses quite a few assumptions.

Ken's site has some good content, but it's mixed in with a lot of misinformation, myths, and misconceptions. I did a quick review of that article; please oblige a brief response to a few of his points:

Bigger pixels collect more light (photons). More photons means more clean image compared to the relatively constant amount of electrons making noise. (Yes, I'm simplifying, but it's why bigger sensors are quieter and cleaner.)

Fatter pixels catch more light, so the larger camera doesn't have to amplify them so much for the same ISO sensitivity. This means that even though we wind up with the same exposure, noise and crud aren't amplified as much, leaving us with a much cleaner images without having to cheat with wimpy noise reduction filtration. There is simply less noise.

This is a myth that I busted on April 25th:

Myth busted: smaller pixels have more noise, less dynamic range ("/forums/t/1055.aspx)

...all cameras smooth over the noise in flat areas to varying amounts where it's most visible...

That's only true for JPEG images, not raw.

the larger format camera sees the subtle difference between the white window frames and the light tan house

This is due to the difference in the spectral response of the color filter array and the JPEG processing, not anything caused by the format size difference.

Aside from those three myths, the information appears to be correct.

More myth info here: http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm ("http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm)

Wikipedia, under "pixel density" sensor section: "Contrary to the popular myth, a high pixel density does not increase noise, decreasing the sensor size does." I think this agrees with your position Daniel.

I'm not sure where all this is going but it is quite a conversation.

All I know is that I am very impressed with the high ISO output of the 5D.In my "subjective observation"the40D generates much more noise at the same ISO. Both are very nice cameras that serve me well. It is also good to note that ISOs are not equivalent between the Canon D series of cameras. The 20D, 30Dand 5D have by default more sensitive ISO bias than the newer 40D and 50D and 5DMII. I think dpreview illustrated this. There's mention of it in several reviews, I know it's in the 40D review. 5D ISO 800 acts more like 1000 yet still seems to produce less/equal noiseas new5DMII at 800.

Now, to me, the most important part of the sensor noise equation has to do with the artificially controlled 1/3 ISO steps on the D series cameras. Obviously this has been shown many times that the ISO sensitivities at 1/3 steps between major ISO sensitivities of 50,100,200,400...etc are generated on a post proccessed level by adding or subtracting numerical values from the RAW output. This is why on a 40D ISO 250 is just as noisy as ISO 400. ISO 320 is better than ISO 250 and about as good as ISO 200.

One of the site's that I find way too deep for anyone (except you Daniel)is http://www.pages.drexel.edu/~par24/rawhistogram/CanonRawScaling/CanonRawScaling.html ("http://www.pages.drexel.edu/~par24/rawhistogram/CanonRawScaling/CanonRawScaling.html)

Canon 5D signal/noise vs. ISO: http://www.pages.drexel.edu/~par24/rawhistogram/5DTest/5DTest.html ("http://www.pages.drexel.edu/~par24/rawhistogram/5DTest/5DTest.html)So, I use 50,100,200,400,1600,3200. on this body

Canon 40D signal/noise vs. ISO: http://www.pages.drexel.edu/~par24/rawhistogram/40DTest/40DTest.html ("http://www.pages.drexel.edu/~par24/rawhistogram/40DTest/40DTest.html)So, I use 160,320,640,800,1250,1600,3200 on this body.

Works very well. I also have a tendency at 640-3200 to use +.3ev just to be able to comp down in post. That would mean my 3200 is actually more like 2400. I very rarely comp down and under expose. That would only help to amplify the output noise level.

For me Daniel it's more of a layman/blue collar approach to all of the technical stuff guys like you, Rockwell, Drexel, etc. talk about. All I need to know is what are the practical settingsand techniques to getthe cleanest images possible. So, keep on splaining........

Chuck

cian3307

05-06-2009, 07:20 AM

Wow. I have been enlightened, some excellent posts above, very informative. thanks everyone. I have been thinking about upgrading to FF at some point but am now thinking the 50D would suit my needs better. I work mainly at the 2 extremes - macro with my 100 f2.8 USM and telephoto with my 300L f4 with 1.4TC. I always try to work in the 100-400 ISO range so noise isn't really a decider.

David Selby

05-06-2009, 11:41 AM

http://learnslr.com/EOSForum/index.php?topic=183.0 ("http://learnslr.com/EOSForum/index.php?topic=183.0)

adam

05-06-2009, 12:05 PM

Wow, lots more info here...thanks! It's kinda what I was afraid of...full-frame would help half of my photographic interests and hurt the other half...

I'm wondering if, when my time comes, instead of springing for a 5DII, I should keep my 40D and pick up a used 5D...kind of a "second-best of both worlds" strategy. And it would cost less money, so I'd be able to replace my crop glass (a Tokina 12-24 and a Canon 60 macro) with better full-frame versions...

JJphoto

05-17-2009, 11:22 AM

a good artical about full fram and crop body from popular photography. link http://www.popphoto.com/Features/The-Full-Frame-Decision

Daniel Browning

05-17-2009, 01:50 PM

a good artical about full fram and crop body from popular photography. link http://www.popphoto.com/Features/The-Full-Frame-Decision

Thanks for the link. I remember reading this when I got it in the mail. Please don't be offended by my criticism of it, but I think the Pop Photo article has very poor treatment of the subject; even Ken Rockwell did a better job.

With more loosely packed pixels, manufacturers can make the pixels bigger, and that’s the case here: A D700 pixel is about 8.5 microns across, while a D300 pixel is about 5.5 microns. Bigger pixels can catch more light, which can make for images that have less noise and greater dynamic range.

I debunked this myth here:

Myth busted: smaller pixels have more noise, less dynamic range, etc. ("/forums/t/1055.aspx)

...for most serious amateurs, and many pros, there is no compelling reason for going to a full-frame DSLR.

There are indeed many reasons, already outlined in this thread, but not mentioned in the article.

Jon Ruyle

05-17-2009, 03:11 PM

...for most serious amateurs, and many pros, there is no compelling reason for going to a full-frame DSLR.

That's just insane.

You don't have to understand the differences between ff and smaller sensors to take great pictures. But you *should* know the difference before you write an article about it. Sigh.

JJphoto

05-17-2009, 05:12 PM

thanks Daniel, what a great subject to talk and think about it!

Jon Ruyle

06-06-2010, 02:49 PM

I'm resurrecting this thread because it seems like a more appropriate place to reply to HiFiGuy1's post, and I didn't want to start a brand new thread called "My reply to HiFiGuy1's post" :)

I believe (and not everyone agrees [:)]) is that a big advantage of FF
is that you get better IQ at wide apertures. The reasons (explained below) hold for pretty much any fast lens.

Why do you think that the 1DsIII + 200 at f4.5
would outperform the 7D + 135 @ f2.8?

This isn't exactly what I said: I that 1DsIII + 200 @ f/2.8 would outperform 7D + 135 @
f/2, and there are two reasons I think this.

First, looking at Bryan's ISO12233 comparison it seems to me that the
200 has a clear (though not what I would call huge) advantage over the
135 (again, both used wide open). The 135 is great, but few lenses perform as well at f/2 as the 200 does at f/2.8.

When you crop, this difference will
only get larger...

Also, why do you say "cropping", based on your
definition of "what you do with crop body" (which to me just alters the
FOV) makes IQ worse?

When you crop, you don't just change the angle of view, you throw
away resolution. Of course, you might object that the 7D has more pixel
density, so even with the smaller sensor it has about the same
resolution as the 5DII. True. But I when I say "throw away
resolution", I don't just mean sensor resolution, but lens resolving
power.

Put another way, when you crop, you don't just crop, you crop then
enlarge to the same size you started with. So all lens flaws are
enlarged. I think this may have been more obvious in the film days because when you start with a small film, you have to enlarge more to get to a given size (say 8x10). Even if the 7D has higher resolution "film" to mostly compensate for this, all other flaws in the picture- including those caused by the lens- will be magnified more.

(Heck, there has to be *some* reason people pay huge $$ for medium frame cameras and lenses that have less versatility than their 35mm counterparts)

When lens quality is high enough (and this probably means stopping down), maybe this lens resolving power
isn't so important because lens flaws are smaller than pixels (ie, we are pixel limited) or maybe even smaller than diffraction discs (ie, diffraction limited). In this case, the
camera with more pixels has better sharpness, and 7D and 5DII are about
the same in this department. But I believe the 135 f/2 is significantly
lens limited when wide open, especially at the high pixel density of
the 7D.

Thus I'm less confident that 7D + 135 @ f/2.8 is sharper than 5DII +
200 @ f/4.5, because this is closer to being a pixel-limited situation.
Not only that, but both lenses are in a zone where stopping down has
less effect on IQ, so the advantage the 200 gains by operating at a smaller f number is
reduced.

Still, I don't think the 135 @ f/2.8 is totally pixel limited. I
think the 5DII + 200 @ f/4.5 would indeed have better IQ.

An APS-C body that reaches DLA around f10 (30D) would have the same DOF
and other properties as a FF at about f16, right? Heck, the APS-C might even be the better
choice in this example, since the FF body that has the same pixel size
and DLA number is the 5D. If it holds true that DOF @ f10 on an APS-C
is roughly equal to DOF @ f16 on a FF, then the sharpness of the APS-C
is probably going to be slightly better.

What matters isn't DLA but how many lines per picture you get with a given DOF. You have to stop down more with full frame by a factor of about 1.6 for far away subjects. This factor changes as you get closer to your subject, and furthermore the size of diffraction discs grows faster than linearly as you get close to 1-1 and beyond. On the other hand, even if you have bigger diffraction discs with FF, the sensor is larger, so it might not be clear which gives better resolution...

At least it wasn't to me until I spent about 20 minutes once writing a bunch of equations :) What I found was that all sensor sizes are the same. That is, if you
want a particular DOF at a particular framing, your diffraction discs
will be exactly proportional to sensor size, and thus you get the same
resolution no matter what your sensor size is. (Sensor resolution is a different issue... but what this says is that diffraction is exactly equally important for two 18mp cameras taking pictures framed the same way and with the same DOF, no matter what the sensor size, assuming all else equal- which it never is.)

I really want to know whether choosing an
APS-H like the 1DIII or 1DIV will be better for me than having an APS-C.
I love my 40D, and I am used to the framing with my lenses on it, but
I'd like to get more from my 17-40L on the wide end and from a sharpness
standpoint. I have been told that the 17-40L thrives on a FF, and is
strangled on an APS-C, cruelly never allowed to blossom to its full
potential.

I don't think there is any question that the 17-40 would be happier
on FF. When you buy a 17-40 you sacrifice IQ, cost, and weight to get a
lens that has a wide angle. When you then put it on a 40D, you then
throw most of that wide image away (together with lens resolving power). If I wanted wide angle on a 40D, I'd get an EF-S lens.

Maybe it only needs APS-H to find happiness? /emoticons/emotion-1.gif

Of course
the 17-40 gets wider on APS-H than APS-C, but then you give up the
ability to use EF-S lenses. Thus, IMO APS-H is the worst size for wide
angle. (Though it is great for a lot of other stuff)

HiFiGuy1

06-06-2010, 04:22 PM

Makes me sad to say it, but I probably ought to sell my beloved 17-40. [:(]I am not doing it justice on my camera. I will miss it, though. It was the first lens I ever bought, and I didn't even have a body yet! Oh well, anybody want an EF 17-40 f/4 L? I guess I need to forget FF and just get a 17-55 f/2.8. [:(]

Jon Ruyle

06-06-2010, 04:29 PM

It was the first lens I ever bought, and I didn't even have a body yet!

Wow. Back then, you *really* weren't using its full potential :)

HiFiGuy1

06-07-2010, 12:52 AM

No, but I was so smitten with the idea of DSLR photography that I wanted to jump in ASAP. That was my first opportunity so I took it. I bought the 17-40 based on Bryan's comments on it being an excellent value in a wide angle L zoom. I also thought I'd be getting a 5D, which I actually did, in a kit with the 24-105, but it didn't have the speed and responsiveness I wanted, so I returned it after a couple of weeks.

I came across a great deal on a NIB 40D kit with the 28-135 that I couldn't pass up, so I got that next. Then came the understanding that my wide angle and my new body weren't necessarily made for each other, and ever since I guess I have been trying to will them to be happy with together. Alas, it was a union that was not meant to be.

This evening on the road on the way to work, I have been pondering alternatives, and I think that if I sell my 17-40 and my 28-135, I will have enough money to get an EF-S 15-85, which seems to be highly regarded. I know it isn't constant f/number across the zoom range, but it certainly seems like an excellent choice from almost every other perspective, and it will work ideally with my 40D, and of course any future APS-C body I might end up with.

To get back to our other discussion, though, I think we are bogging down with the wide open comparison on the two actual lenses that I chose originally, when the point of the discussion is at least somewhat theoretical. That is why I shifted to the 5DII + 200 at 4.5 and 7D + 135 @ 2.8. That allows the lenses to be nearly interchangeable optically and DOF, and then we are only comparing the performance of the combos from a resulting image standpoint, with the consideration for an 8% crop of the FF to match the framing of the other combo. This even makes the resulting resolution similar.

The rationale, though my train of thought may have been derailed by the long drive, is that for a lot less money, I can get FF results with an APS-C and a carefully chosen companion lens. I know there are certain things that will only be possible with FF, because it is mathematically impossible to achieve them with a crop body, but for the vast majority of my shooting, with properly chosen lenses, I won't miss the FF experience at all.

I had also been questioning the efficacy of APS-H, as it relates to the compromise with both APS-C and FF, which I still am interested in hypothetically, but I decided on the way here that I am having a crisis of conscience financially, and can't make myself spend the money right now on a 1D3 or 1D4. I could talk myself into it in a heartbeat, but I shouldn't do that for the moment, and I am trying to be responsible.

My aspirations for now are to be able to shoot residential (indoor) architecture, portraits, macro and birds/air shows. I feel like I will be able to do this at least adequately with two lenses for now, which are the 15-85 and either a 300/4 or 400/5.6, though I am leaning towards the 300 because it will also double as a near-macro like the 400mm Sigma TeleMacro I just sold (Nikon mount). The 15-85 should be wide and long enough to get the architecture and portraits. I am also looking at the 17-55, but honestly it doesn't seem like it is better in practice than the 15-85, and it lacks width and length, and has a less sophisticated IS, a full stop short. It is almost too good to be true that the 15-85 is $400+ cheaper. It lacks the 2.8 constant, but especially on the wide end, I would be stopped down anyway, probably. If I really needed the narrow DOF on the longer end, I could just get an 85/1.8 and stop it down to 2.2 or 2.8. The combo would be about what the 17-55 costs alone. What do you think about that?

neuroanatomist

06-07-2010, 11:56 AM

That is why I shifted to the 5DII + 200 at 4.5 and 7D + 135 @ 2.8....then we are only comparing the performance of the combos from a resulting image standpoint

No, you're not. Oh boy. Let me start by saying that I don't want to re-launch my discussion with Jon, but at the same time, we touched on several of these issues recently. My main point from that discussion was that you really cannot compare bodies and lenses at the same time like that. If you read Bryan's comments on how to use the ISO 12233 charts, he makes a clear point that lenses only should be compared with other lenses on the same body, and bodies should be compared with other bodies only when using the same lens (for that, he recommends the 200mm f/2L and the 200mm f/2.8L II, since he's shot the charts with several bodies using those lenses, presumably intentionally to allow comparison across bodies). The only way to actually compare those two combinations is to shoot the same test shots with those specific combinations, i.e a 5DII body, a 7D body, and the pair of different primes (or a zoom lens set to different focal lengths and apertures) to compensate for the sensor crop factor.

But, HiFiGuy1, let's take a few of your statements and look at them:

I can get FF results with an APS-C and a carefully chosen companion lens

No, this isn't really true. With an APS-C body, you can choose a lens to match the aperture and focal length that you would achieve on a FF body with a different lens (e.g. 85mm f/1.2 on crop body, 135mm f/2 on FF; or, 50mm f/1.2 on crop body, 85mm f/1.8 on FF). The focal lengths and max apertures will be equivalent. But the results will not be the same. First and foremost, ISO noise will be higher on the crop body - that alone will make a big difference in the types of things you want to shoot. One of Jon's valid points from our recent discussion is that cost is also a consideration - in the examples above, getting the 135mm f/2 and85mm f/1.8 to use on FF would cost about ~$2K less than getting the85mm f/1.2 and50mm f/1.2 to use on a crop body (that difference would almost buy the 5DII!!).

You're right thatcertain things that will only be possible with FF - the razor-thin DoF of an f/1.2 lens on FF is one example.

I had also been questioning the efficacy of APS-H, as it relates to the compromise with both APS-C and FF,

I don't think it's a good compromise, either. Personally, the combination of a good crop body (e.g. 7D) with a 5DII would make a much better option than a 1DIII or 1DIV body, for about the same cost.

The 15-85 should be wide and long enough to get the architecture and portraits.

Wide enough for architecture, probably. But the other issue there is distortion. Buildings have straight lines. At the wide end, the 15-85mm suffers badly from barrel distortion (3.15%). By comparison, the 17-55mm at 17mm has 2% barrel distortion, and the 10-22mm at 10mm is quite good, with only 1.25% barrel distortion. Also, some interior spaces really need wider - that's where the EF-S 10-22mm f/3.5-4.5 is useful; the minimal amount of distortion with that lens make it one of the better choices for architecture (short of a tilt-shift lens).

On the long end, I think you'd find that the 15-85mm for portraits will, in a word, suck. I should qualify that by saying that it would work in a studio setting, where you have total control over lighting and especially background (pull-down backdrops). But if you can't simply lower a contrived featureless background into place, the OOF blur and subject isolation you want in a portrait aren't going to happen at 60-85mm f/5.6.

So, on the whole I think the 15-85mm is probably not a great lens for your uses - too much distortion for architecture at the wide end, too narrow an aperture for portraits at the long end. It's a compromise lens, but with too many compromises. I think for a point-and-shoot user coming to dSLRs, it would be a very nice lens.

If I really needed the narrow DOF on the longer end, I could just get an 85/1.8 and stop it down to 2.2 or 2.8.

That makes sense. The 85mm f/1.8 is a great close-up and head/shoulders portrait lens on a 1.6x body.

You might actually consider 10-22mm, 85mm f/1.8, and the 100-400mm instead (I find the 100-400mm to be much more versatile than the 300mm prime; you mention air shows, Bryan calls the 100-400mm the best air show lens).

Just my 2¢. Good luck with your decisions!

--John

HiFiGuy1

06-07-2010, 06:44 PM

neuronatomist,

"...but I decided on the way here that I am having a crisis of conscience financially, ... and I am trying to be responsible."

When you suggest the 10-22 + 85/1.8 + 100-400, I think you forgot about the above. [;)] I don't want to go into worse (or inappropriate, in the case of the 17-40) glass from my current 17-40 and 28-135, but I can't really spend a bunch more money. Also, the trio you suggested leaves a hole in the general purpose area. I do love the idea of a 17-55, but I am not sure it has enough range, and it is almost twice the current price of a 15-85. Is that lens THAT bad? Unless I am misreading the review, Bryan seems to quite like it.

If I had the cash, I would probably like to have the 10-22, 17-55, 85/1.8, 100/2.8 IS macro and a telephoto plus a 1.4x. I won't say I wouldn't own one, but I have used the 100-400 and really don't dig the push-pull zoom. If they made that range in a normal zoom lens, I would be all over it. I have no real problem with the IQ, just the functionality. I might get used to it, but I haven't had that opportunity yet.

neuroanatomist

06-07-2010, 07:11 PM

15-85. Is that lens THAT bad? Unless I am misreading the review, Bryan seems to quite like it.

It's a very nice lens, when used as a general purpose zoom (especially outdoors). But although architecture and portrait shots may fall into the focal length range covered by a general purpose zoom lens, those types of shooting are specific, not general. Although the 15-85mm is a fine lens, personally, I don't think it's well suited to architecture and portrait shooting. Vacation pictures, pictures of a family outing or gathering (even indoors with an external Speedlite), etc. - for that sort of thing, it's a good option.

Jon Ruyle

06-07-2010, 08:14 PM

I think we are bogging down with the wide
open comparison on the two actual lenses that I chose originally, when
the point of the discussion is at least somewhat theoretical.

I think the reasons I gave apply to any lens... it's just that the difference matters less for lenses that are more pixel limited.

I know there are certain things that will only
be possible with FF, because it is mathematically impossible to achieve
them with a crop body

I don't think there are
mathematical or physical limitations on small sensors, at least, not
ones that are relevant to our discussion.

The focal lengths and max apertures will be equivalent. But the results will not be the same. First and foremost, ISO noise will be higher on the crop body - that alone will make a big difference in the types of things you want to shoot.

If you set things up so the shutter speed is the same, the noise will *not* in general be higher on the crop body. Photon noise will be the same, assuming the sensors have the same quantum efficiency (I believe the 7D has a slight edge over the 5DII here). Read noise could be higher or lower, who knows. The 7D has lower read noise overall, but there may be particular situations in which the 5DII has lower read noise.

Results will indeed, modulo specific attributes of the particular lens and body chosen (like IQ [:)]), be the same.

neuroanatomist

06-07-2010, 09:34 PM

<div>

I have used the 100-400 and really don't dig the push-pull zoom. If they made that range in a normal zoom lens, I would be all over it. I have no real problem with the IQ, just the functionality.

I actually find it to be beneficial. Often, when shooting birds for example, you want to just zoom to 400mm and use it. (Yes, the 400mm f/5.6L prime is cheaper, lighter and smaller, but it lacks IS). In rapidly changing situation like an air show or outdoor sports, the speed with which you can adjust the focal length is an advantage over a rotating zoom ring, IMO.

I don't think there are
mathematical or physical limitations on small sensors, at least, not
ones that are relevant to our discussion.
</div>

Not of the sensor, per se. But as I mentioned above, getting the equivalent DoF of an f1.2 lens on FF at <100mm focal lengths on a crop body isn't physically possible (barring the release of an f/0.75 lens).

Keith B

06-07-2010, 09:57 PM

<div>

I have used the 100-400 and really don't dig the push-pull zoom. If they made that range in a normal zoom lens, I would be all over it. I have no real problem with the IQ, just the functionality.

I actually find it to be beneficial. Often, when shooting birds for example, you want to just zoom to 400mm and use it. (Yes, the 400mm f/5.6L prime is cheaper, lighter and smaller, but it lacks IS). In rapidly changing situation like an air show or outdoor sports, the speed with which you can adjust the focal length is an advantage over a rotating zoom ring, IMO.

</div>

Love the push pull! Air shows and football, it is so quick to go in and out as a runner is coming at you or going away.

HiFiGuy1

06-08-2010, 12:21 AM

Sounds good. The interesting thing to me was that I actually liked the concept originally, but when I tried it, it felt really weird. If you guys like yours so well, I guess I should give it more consideration. I will still have to wait a while, though. I am going to have to get a more general purpose lens with the money from the sale of my two current lenses and be happy with that for now. John kind of has me talked out of what I thought was nearly the ideal lens for my immediate needs in the EF-S 15-85, and has me thinking long and hard about the 17-55 instead. I love the speed and the sharpness, but I just wish it had more range on the long end. Whichever I get, it will be my only purchase for a while, notwithstanding an L-bracket.

Keith B

06-08-2010, 12:31 PM

Sounds good. The interesting thing to me was that I actually liked the concept originally, but when I tried it, it felt really weird. If you guys like yours so well, I guess I should give it more consideration.

It did feel weird at first but after time it felt very natural. For me it was getting use to using the tension ring. There is never one right setting for me, I love that I can have different tension and speed for different applications.

Roland Scheiner

06-13-2010, 04:04 PM

I have both the 5D2 with the handgrip and the 1D4, a 16-32; 24-105, 28-135 and a 70-300 and a 580 EX flash. In about 3 weeks I will join a group of tourists on a bustour all trough Ireland. (I live in Germany). It is clear, that I can`t take the whole gear with me. So question what is the most apprpriate solution.

I tend to take the 5D2 plus the 24-105 an the 70-300 with me, and the flash. Why not the 1D4? It has all the features of the 5D2 and few more, which I probably will not need during the tour (for example 10fps/sec). The 1,3 crop of the 1D4 is, so I think in this case a bit of a disadvantage. I only have place in the bag I will use for 1 body and 2 lenses. The wide angle with the 1D4 and the 24-105 is 31.2; not very much for a wideangle. My expierience in 35 years of touristic photoshooting is, that you need more often a wideangle than an telephotolens beyond of 180. But to save place and weight and to only take the 28-135 would restrict
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 the possibilities too much.

So what do you think.

Maybe Canon brings a few perfectly adapted lenses for 1,6 crop covering the same angle than FF lenses. Or a 1D5 to come is a FF body.