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Misleading FF vs Crop examples

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Pultzar

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It is common to see comparisons of crop vs FF cameras. This is how most tests seem to be performed:

-Both cameras at the same ISO
-Both cameras at the same shutterspeed
-Both cameras at the same f-stop
-Both cameras with the same lens with one camera positioned differently OR each
camera having a different lens equating to the same 35mm focal length.

The problem here is that the above will create a different image between the cameras since the DOF is different between the FF and the Crop camera. This is what I would propose instead:

-Both cameras at the same shutterspeed
-Both cameras in the same position
-FF lens is 1.6X focal length of the crop lens (ie 135mm and 85mm respectively)

-Aperature diameter is set the same, which means that the FF camera should be stopped down. For example f/5.6 for FF and f/3.5 for the crop if my numbers are right.

-ISO should be set on one camera and then matched on the other camera to produce the same exposure. If you have to bump the ISO up on the FF camera to achieve this, so be it.

Now both images with have the same perspective, shutter speed, exposure, and DOF.

In this test, I'm guessing that noise for the FF camera will become slightly worse since you are no longer shooting at the same f-stop. However sharpness and other qualities should improve since you are stopping down the lens.

Unfortunately you still have the problem of two different lenses. This is impossible to get away from even when using thes same lens, since between FF and crop you are using different parts of the lens anyway.

Do these tests exist someplace? I suppose my biggest beef is that comparing cameras using procedure #1 creates a different image beyond the artifacts that the camera/lens create.
 
When I say that the FF will become worse in respects to noise, I mean compared to the other testing scenario and not compared to the crop camera.
 
I am working on such a test - 5DII vs 7D. It's not ready for public consumption yet, but I can tell you, to make a long story short, the 5DII wins no matter how you slice it.
 
Where's the comparisons between FF and Crops?

Here's the thing, if you did change the settings to equal the 35mm equivalents that would be misleading as the 1.6 crop is not 35mm so the differences should be shown at equal FL,ISO,Aperture,SS etc...IMO...
Pultzar said:
It is common to see comparisons of crop vs FF cameras. This is how most tests seem to be performed:

-Both cameras at the same ISO
-Both cameras at the same shutterspeed
-Both cameras at the same f-stop
-Both cameras with the same lens with one camera positioned differently OR each
camera having a different lens equating to the same 35mm focal length.

The problem here is that the above will create a different image between the cameras since the DOF is different between the FF and the Crop camera. This is what I would propose instead:

-Both cameras at the same shutterspeed
-Both cameras in the same position
-FF lens is 1.6X focal length of the crop lens (ie 135mm and 85mm respectively)

-Aperature diameter is set the same, which means that the FF camera should be stopped down. For example f/5.6 for FF and f/3.5 for the crop if my numbers are right.

-ISO should be set on one camera and then matched on the other camera to produce the same exposure. If you have to bump the ISO up on the FF camera to achieve this, so be it.

Now both images with have the same perspective, shutter speed, exposure, and DOF.

In this test, I'm guessing that noise for the FF camera will become slightly worse since you are no longer shooting at the same f-stop. However sharpness and other qualities should improve since you are stopping down the lens.

Unfortunately you still have the problem of two different lenses. This is impossible to get away from even when using thes same lens, since between FF and crop you are using different parts of the lens anyway.

Do these tests exist someplace? I suppose my biggest beef is that comparing cameras using procedure #1 creates a different image beyond the artifacts that the camera/lens create.
Click to expand...
--
Slainte (cheers)

You cannot depend on your eyes when your imagination is out of focus. :- Samuel Langhorne Clemens
 
As you point out, there is no way to control for all variables. Either use the same lens and have different fields of view, or get the same field of view and introduce lens variables.

There are a few ways out of this bind:

Decide that either type of system is plenty good for your photography and make decisions based on important factors other than system resolution. For most people this makes a ton of sense.

Think of a comparison between the "best" overall system on one format and the roughly comparable system on the other. For example if your choice of a cropped sensor body would lead you to use the EFS 17-55mm f/2.8 IS, while your choice to get a full frame body would lead you to, for example, the EF 24-70mm f/2.8... Compare those two real world systems.

Go with the known real world characteristics of the two formats, including the fact that when all fother actors are equivalent a larger format always has greater resolution potential.

Dan
Pultzar said:
It is common to see comparisons of crop vs FF cameras. This is how most tests seem to be performed:

-Both cameras at the same ISO
-Both cameras at the same shutterspeed
-Both cameras at the same f-stop
-Both cameras with the same lens with one camera positioned differently OR each
camera having a different lens equating to the same 35mm focal length.

The problem here is that the above will create a different image between the cameras since the DOF is different between the FF and the Crop camera. This is what I would propose instead:

-Both cameras at the same shutterspeed
-Both cameras in the same position
-FF lens is 1.6X focal length of the crop lens (ie 135mm and 85mm respectively)

-Aperature diameter is set the same, which means that the FF camera should be stopped down. For example f/5.6 for FF and f/3.5 for the crop if my numbers are right.

-ISO should be set on one camera and then matched on the other camera to produce the same exposure. If you have to bump the ISO up on the FF camera to achieve this, so be it.

Now both images with have the same perspective, shutter speed, exposure, and DOF.

In this test, I'm guessing that noise for the FF camera will become slightly worse since you are no longer shooting at the same f-stop. However sharpness and other qualities should improve since you are stopping down the lens.

Unfortunately you still have the problem of two different lenses. This is impossible to get away from even when using thes same lens, since between FF and crop you are using different parts of the lens anyway.

Do these tests exist someplace? I suppose my biggest beef is that comparing cameras using procedure #1 creates a different image beyond the artifacts that the camera/lens create.
Click to expand...
--
---
G Dan Mitchell - SF Bay Area, California, USA
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Pultzar said:
. . . Unfortunately you still have the problem of two different lenses. This is impossible to get away from even when using thes same lens, since between FF and crop you are using different parts of the lens anyway.
Click to expand...
let the fact enter your thoughts that bigger is better - always (at least in photography)

The more image area you cover the better it is - even today.

DOF, FOV and optical quality of the lenses count in. So it may be that some 35 mm equivalent cameras get near the image quality range of a mediocre medium format digital back simply because some algorithms are not that good or some lenses are still from the analog times where color fringing was not that critical but a good medium format digital back will always beat a FF DSLR at the same MP count and equivalent focal length! always!

With respect to smaller sizes it is even worse since the MP count is sometimes the USP (unique selling point) and thus the manufacturers concentrate on this aspect more then on others.

So the short answer would be: Bigger is better

IMHO everything below FF is rubbish if you want a reasonable quality under lots of conditions - if you want extraordinary results with high resolution you can use tilt and shift lenses and stitch some three of four frames or get a one shot medium format DSLR and enjoy the printed quality.

I am printing regularly for friends with my Z3200 printer and see results from F7 / D450 or D50 compare to my 5D II results - most of the time with heavy noise and quite unsharp (even though the AF is supposed to be better compare to my 5D II)

A skilled photographer will succeed in better results with a larger sensor compare to a smalller one. Having said that - a skilled photographer may do good images also with a smaller sensor but it will never reach the same quality level in terms of noise, resolution and color depth.

There is no hype around ff - there is a need for it and there is even an need for a bigger format sometimes - I'd love to go back to the time where I sued my 5x7 inch Plaubel but with the weight and size of my 5D II :-)

Nobody needs tests with the same aperture independent from the format because the DOF is differnt with respect to the image size.

In large format f/22 was normal - in 35 mm f/8 is a kind of normal aperture and at 1,6 crop factor it is f/5.6 (more or less)

The creative deviation from this aperture is the same for every format and in the eye of the photographer.

There is no test that will proof something different and there will be no test that gives you a "good boy feeling" for spending less money.

Crop is worse then ff, ff is worse then medium format and medium format is worse then large format but sometimes a point and shoot is all you may want to cary and thus it may be your right choice.

PROs always use what suits their needs - only amateurs start arguing that smaller is better.

just my 2 ct

P.S. I am as happy as can be with my 5D II and I was attracted by the first images I saw and I still never saw a better printed quality compare to my 5 D II to date and I am looking forward to the 5D II next year with a few refinement in some aspects. Maybe some day I will be able to afford a P65+ successor with contemporary feature set.

here are some stitched virtual 56x36 mm senor size results made with my TS-E 17
http://www.jo-1.de/industry-art/index.html
--

isn’t it funny, a ship that leaks from the top

ISO 9000 definition of quality: 'Degree to which a set of inherent characteristic fulfills requirements'
I am the classic “Windows by Day, Mac by Night user'

“The horizon of many people is a circle with zero radius which they call their point of view.” Albert Einstein
 
I agree with what you say. I'm not sure if you were implying this, but I don't recall arguing that crop is better than FF. I was rather arguing the method that people use to compare them.
 
Pultzar said:
I agree with what you say. I'm not sure if you were implying this, but I don't recall arguing that crop is better than FF. I was rather arguing the method that people use to compare them.
Click to expand...
I was reading between the lines - for what do you need a test setup? What do you want to compare?

The best is always printing and putting it on an exhibition wall and wait what sells best ;-)

Printing is IMHO the only way to compare things. No matter what you start with - the end result counts and that should IMHO be a larger print - large enough to express what you want to show - the larger you print the more the shortcomings of smaller sensors are emphasized.

just my 2ct (again)

P.S: the methodology for comparing sensor sizes can only be one: get the best lens in each sensor size and try to adapt FOV and DOF and print them both at the same size and look at the results.

--

isn’t it funny, a ship that leaks from the top

ISO 9000 definition of quality: 'Degree to which a set of inherent characteristic fulfills requirements'
I am the classic “Windows by Day, Mac by Night user'

“The horizon of many people is a circle with zero radius which they call their point of view.” Albert Einstein
 
joger said:
let the fact enter your thoughts that bigger is better - always (at least in photography)
Click to expand...
Maybe if you look at photography as a study in engineering. Many regard it as an art.
joger said:
The more image area you cover the better it is - even today.
Click to expand...
What if the optical quality of the lenses you're using don't match the size you're intending to cover? What you say is purely theoretical because as the size increase there are many situations where you can't take an image at all, or where its highly impractical.

Presumably often the tests are really trying to see how the sensors compares in performance. If you have a smaller sensor that performs to a superior level than a larger sensor, overall there will be an IQ benefit. All sensors are not created equal, otherwise companies wouldn't need to invest millions to advance the technology.

Even then the quality of the sensor is still subject to the quality of the lens you put in front of it, and far more subject to the quality of the light that you're shooting in.

With digital technology we're rapidly approaching the point where image quality differences exist only at a theoretical level.
joger said:
DOF, FOV and optical quality of the lenses count in. So it may be that some 35 mm equivalent cameras get near the image quality range of a mediocre medium format digital back simply because some algorithms are not that good or some lenses are still from the analog times where color fringing was not that critical but a good medium format digital back will always beat a FF DSLR at the same MP count and equivalent focal length! always!
Click to expand...
joger said:
With respect to smaller sizes it is even worse since the MP count is sometimes the USP (unique selling point) and thus the manufacturers concentrate on this aspect more then on others.

So the short answer would be: Bigger is better
Click to expand...
No its simple bigger is just bigger - better is a purely subjective assessment.
joger said:
IMHO everything below FF is rubbish if you want a reasonable quality under lots of conditions - if you want extraordinary results with high resolution you can use tilt and shift lenses and stitch some three of four frames or get a one shot medium format DSLR and enjoy the printed quality.
Click to expand...
Hate to burst your bubble but there's plenty of smaller sensor/lens combinations that meet or exceed their FF equivalents, for the simple reason that the tradeoff required to cover a larger sensor would result in optics that would be impractical for general use or prohibitively expensive.

You can also stitch together images from smaller cameras to get exactly the same result?
joger said:
I am printing regularly for friends with my Z3200 printer and see results from F7 / D450 or D50 compare to my 5D II results - most of the time with heavy noise and quite unsharp (even though the AF is supposed to be better compare to my 5D II)
Click to expand...
The 5 year old Nikon presumably with kit lenses don't keep up with your 5D - kinda expected though wouldn't you say?
joger said:
A skilled photographer will succeed in better results with a larger sensor compare to a smalller one. Having said that - a skilled photographer may do good images also with a smaller sensor but it will never reach the same quality level in terms of noise, resolution and color depth.
Click to expand...
A skilled photographer probably realizes that the essence of the image isn't really in its size.

If you start stitching together multiple images you can identical results in terms of noise, color depth and dynamic range because you're not limited to a single exposure.
joger said:
There is no hype around ff - there is a need for it and there is even an need for a bigger format sometimes - I'd love to go back to the time where I sued my 5x7 inch Plaubel but with the weight and size of my 5D II :-)

Nobody needs tests with the same aperture independent from the format because the DOF is differnt with respect to the image size.

In large format f/22 was normal - in 35 mm f/8 is a kind of normal aperture and at 1,6 crop factor it is f/5.6 (more or less)

The creative deviation from this aperture is the same for every format and in the eye of the photographer.

There is no test that will proof something different and there will be no test that gives you a "good boy feeling" for spending less money.
Click to expand...
There are plenty of cameras that are more suited to the needs of photographers than FF. If you want large resolution and ultra-shallow DOF it makes sense. If you want super-telephoto in a package that's still portable its probably not the best option.
joger said:
Crop is worse then ff, ff is worse then medium format and medium format is worse then large format but sometimes a point and shoot is all you may want to cary and thus it may be your right choice.

PROs always use what suits their needs - only amateurs start arguing that smaller is better.
Click to expand...
So why is it that there's plenty of pros using crop cameras, just as others use FF and others still use MF? Maybe not everyone has the same needs or subjective assessment of what is "better".
joger said:
just my 2 ct

P.S. I am as happy as can be with my 5D II and I was attracted by the first images I saw and I still never saw a better printed quality compare to my 5 D II to date and I am looking forward to the 5D II next year with a few refinement in some aspects. Maybe some day I will be able to afford a P65+ successor with contemporary feature set.

here are some stitched virtual 56x36 mm senor size results made with my TS-E 17
http://www.jo-1.de/industry-art/index.html
--
Click to expand...
And this is meant to be evidence of something that couldn't be done with just about any digital camera and photoshop?

Nice to see that you're happy with your FF camera and expensive lenses.

--
Veo el mundo: http://www.veoelmundo.com my blog about travel photography
 
Hi JackM,
JackM said:
I am working on such a test - 5DII vs 7D. It's not ready for public consumption yet, but I can tell you, to make a long story short, the 5DII wins no matter how you slice it.
Click to expand...
While mostly 5DII is better than 7D,

IMHO, I think sometimes 7D wins over the 5DII.
  • If the object is smaller than 2 cm, like coins, small insect, etc. 7D will deliver sharper & detailed pictures, no ?
  • How about photographing the moon ?
  • and maybe on tracking moving object, BIF, sport, etc ?
No disrespect to your post here,
I just like both 5DII & 7D.

-
Brian
 
gdanmitchell said:
As you point out, there is no way to control for all variables. Either use the same lens and have different fields of view, or get the same field of view and introduce lens variables.

There are a few ways out of this bind:

Decide that either type of system is plenty good for your photography and make decisions based on important factors other than system resolution. For most people this makes a ton of sense.

Think of a comparison between the "best" overall system on one format and the roughly comparable system on the other. For example if your choice of a cropped sensor body would lead you to use the EFS 17-55mm f/2.8 IS, while your choice to get a full frame body would lead you to, for example, the EF 24-70mm f/2.8... Compare those two real world systems.
Click to expand...
That's make sense to me.
gdanmitchell said:
Go with the known real world characteristics of the two formats, including the fact that when all fother actors are equivalent a larger format always has greater resolution potential.
Click to expand...
Not always.
Moon and objects that smaller than 2cm will lead to 7D advantage.
7D will have greater resolution potential over 5DII.

-
Brian
 
Silverback1988 said:
JackM said:
I am working on such a test - 5DII vs 7D. It's not ready for public consumption yet, but I can tell you, to make a long story short, the 5DII wins no matter how you slice it.
Click to expand...
While mostly 5DII is better than 7D,

IMHO, I think sometimes 7D wins over the 5DII.
  • If the object is smaller than 2 cm, like coins, small insect, etc. 7D will deliver sharper & detailed pictures, no ?
Click to expand...
At best, in controlled situations like these, it's a tie, and that's being kind. The only time the 7D beats the 5DII is when you need more reach. At 200mm on a 70-200, yes, of course the 7D resolves more detail, but that's a special case. Creating the same composition with both cameras, the 5DII just has better IQ. It is close though, and you won't see the difference until printing very large or viewing at 100%.
Silverback1988 said:
  • How about photographing the moon ?
Click to expand...
Haven't tried that.
Silverback1988 said:
  • and maybe on tracking moving object, BIF, sport, etc ?
Click to expand...
I've been shooting youth soccer this fall. Center point to center point, I'm not sure the 7D is any better than the 5DII, which is a let-down, especially coming from a 1DIIN. That's also a compliment to the 5DII, the center point is really quite good. However I feel that using the center point on any camera isn't the best idea for Soccer. I like to use the top point and put it on the player's face. In that regard the 7D is superior to the 5DII. One thing that is really awesome about the 7D is that you can tell it to automatically switch points when you hold it in portrait or landscape position. Another plus for the 7D is that I was able to use my 70-200/2.8II without any teleconverters and cover a good portion of the field. I think a 1D and definitely the 5D would need a TC to shoot soccer effectively with a 70-200.
 
Pultzar said:
It is common to see comparisons of crop vs FF cameras. This is how most tests seem to be performed:

-Both cameras at the same ISO
-Both cameras at the same shutterspeed
-Both cameras at the same f-stop
-Both cameras with the same lens with one camera positioned differently OR each
camera having a different lens equating to the same 35mm focal length.

The problem here is that the above will create a different image between the cameras since the DOF is different between the FF and the Crop camera. This is what I would propose instead:

-Both cameras at the same shutterspeed
-Both cameras in the same position
-FF lens is 1.6X focal length of the crop lens (ie 135mm and 85mm respectively)

-Aperature diameter is set the same, which means that the FF camera should be stopped down. For example f/5.6 for FF and f/3.5 for the crop if my numbers are right.

-ISO should be set on one camera and then matched on the other camera to produce the same exposure. If you have to bump the ISO up on the FF camera to achieve this, so be it.

Now both images with have the same perspective, shutter speed, exposure, and DOF.

In this test, I'm guessing that noise for the FF camera will become slightly worse since you are no longer shooting at the same f-stop. However sharpness and other qualities should improve since you are stopping down the lens.

Unfortunately you still have the problem of two different lenses. This is impossible to get away from even when using thes same lens, since between FF and crop you are using different parts of the lens anyway.

Do these tests exist someplace? I suppose my biggest beef is that comparing cameras using procedure #1 creates a different image beyond the artifacts that the camera/lens create.
Click to expand...
On the contrary, the type of test that you initially described is exactly what should be done. I want a test that shows the differences between Full Frame and APS-C. I'm not interested in seeing the situations in which the two are manipulated to be equalized; I want to see the differences (and/or advantages vs disadvantages).

I believe in the difference (Viva la difference), trying to normalize or equalize the two negates the advantages of both. I want to know that with the same lens at the same aperture, at the same shutter and at the same ISO the type of image I will receive from both camera sensors. From there I will know which better suits my needs.

I don't know about other Full Frame users but I have never, not one time, thought to myself right before taking a picture, "Ok I have a full frame camera, in order to equal my 550D here I need to change my aperture to f/X.X and my focal length to XXmm." Nor is the reverse true when using my 550D.

Just my opinion.

--
http://www.photopurity.com
 
Holgs said:
Hate to burst your bubble but there's plenty of smaller sensor/lens combinations that meet or exceed their FF equivalents, for the simple reason that the tradeoff required to cover a larger sensor would result in optics that would be impractical for general use or prohibitively expensive.
Click to expand...
This is only true when you are focal-length limited. But indeed, a 70-200 on APS-C is a powerful combo.
 
MajStriker said:
I don't know about other Full Frame users but I have never, not one time, thought to myself right before taking a picture, "Ok I have a full frame camera, in order to equal my 550D here I need to change my aperture to f/X.X and my focal length to XXmm." Nor is the reverse true when using my 550D.
Click to expand...
Absolutely agree. You look through the VF and compose the shot as you want to see it, and that is that.
 
I use both 5DII and 7D for my wedding working. No amount of testing and comparisons will change my opinion about these two cameras. The only test that matters to me is what I see and observe when I’m out there using the two cameras in real world situation.

My go to camera is 5DII period. It is not even close.
 
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