Comparison of Image Quality Canon 1Dmk4 and Canon 7D

[Grant Atkinson]

For those with an interest in seeing images taken in the same conditions, from the Canon 1Dmk4 and the Canon 7D, I have carried out a comparison and posted it on my blog.
I will carry out more comparisons as time permits, but this one sets out to provide information for those wondering how heavily the Mk4 files can be cropped, and how the image quality holds up.
See the comparison and images here:

http://grantatkinsonphotography.blogspot.com/2012/02/image-quality-comparison-canon-1dmk4.html

cheers
Grant

[daddie2610]

For those with an interest in seeing images taken in the same conditions, from the Canon 1Dmk4 and the Canon 7D, I have carried out a comparison and posted it on my blog.
I will carry out more comparisons as time permits, but this one sets out to provide information for those wondering how heavily the Mk4 files can be cropped, and how the image quality holds up.
See the comparison and images here:

http://grantatkinsonphotography.blogspot.com/2012/02/image-quality-comparison-canon-1dmk4.html

cheers
Grant

The APS-C sensor in the 1Dmk4 is 27.9mm long and 18.6mm high. When the image circle is projected from the rear of the lens, more of it falls onto this sensor then the smaller sensor in the 7D, hence the wider field of view, with more background visible.
The APS-H sensor in the 7D is 22.3mm long and 14.9mm high. When the image is projected from the rear of the lens, this smaller sensor can only record over its smaller surface.

Grant just a mistype from you shouldn't this just be the other way around?

[Loyiso]

The 7D seems to be holding its own at ISO 400. It would be interesting to see, when you post these later, how much different the picture is at high ISO levels. Thanks for the comparison.

[Grant Atkinson]

Thanks for the feedback there guys, I have corrected the typo, and switched C and H around as they should have been, much appreciated.

[Grant Atkinson]

Hi Loyiso
Whilst the 7D image quality does look fine at ISO400, it is in fact the Mk4 file that is getting its ISO performance tested when it is being viewed at greater effective magnifications if that makes sense!
According to some of the more scientific sensor tests I have read up on, once you equalize for subject size, for want of a better term, the results should be similar, which they are as this shows. Will be greater differences when the Mk4 image is not heavily cropped...
cheers
Grant

[Green Gorilla]

Thanks Grant, nice read... just wondering, under your Zebra images, what is a 7Dmk4?

[cagenuts]

Nice review Grant. My eyes tell me the results at ISO400 are pretty much on par.

[Loyiso]

Hi Loyiso
Whilst the 7D image quality does look fine at ISO400, it is in fact the Mk4 file that is getting its ISO performance tested when it is being viewed at greater effective magnifications if that makes sense!
According to some of the more scientific sensor tests I have read up on, once you equalize for subject size, for want of a better term, the results should be similar, which they are as this shows. Will be greater differences when the Mk4 image is not heavily cropped...
cheers
Grant

Thanks Grant. Yes, it makes sense.

[Grant Atkinson]

Hi GG, another typo, was so excited after SA thumped the Kiwis at cricket
I will go fix it now..thanks for that
cheers
Grant

[Grant Atkinson]

Thanks for the comments Hilton, Loyiso and GG
These comparisons are not usually as straightforward as they seem, because the two cameras have quite different sensor physical dimensions, AND different sized pixels on those sensors. It will be, much easier to compare one full frame camera with another!
When you look at a DXO mark comparison of these two sensors, the 1Dmk4 will be rated a lot higher than the 7D but DXO Mark do not take into account the size of the subject and cropping.
In the real world the three ways I can think of for equalizing the difference in subject size that exist between cameras with big pixels and cameras with small pixels are to: Move closer, Use a longer focal length or Crop. The comparison that I carried out was for the crop option. The other two methods will yield somewhat different results in image quality. Feel free to add other options too
Hilton, they should be similar comparing at iso 400 using the cropping method, as the 7D and 1Dmk4 sensors are from the same Canon sensor technology era.
cheers
Grant
Cheers
Grant

[Jeffreysa]

Thanks Grant. It will be very interesting to see the comparisons at higher ISO setting using the crop method. Your hard work is very much appreciated by all those interested in this study, which I'm sure are many.