Tuesday, 22 February 2011

Canon 7D v 5Dmk2 - a bit of pixel peeping

Just over a week ago while I was at Slimbridge I was in one of the hides on my own and so was lucky enough to have the beautiful Common Buzzard that is the subject of today's blog all to myself, in beautiful sunlight.

It hung around for quite a while as it was intently study a vole in the field ahead of it, which it subsequently caught and flew off with.  This gave me the chance to change around body, lens and converter compositions to see how things looked and how the crop worked.

The first two images are full frame in terms of crop, and then I will do some 100% pixel blow ups.  (Click on the image to see it larger)

5Dmk2, 500f4, 1.4EFTC, 100% of the image

7D, 500f4 (no TC) 100% of the image

Summary - the 1.4 on the 5D nearly makes up for the 1.6 crop factor on the 7D.  Both images are within 1 kelvin on the colour temperature, but the 7D is warmer due to it being shot about 20 minutes earlier, and the sun was brighter.

5Dmk2, 500f4, plus 1.4EFTC, crop at 100% pixel enlargement - Unsharpened!!

7D, 500f4, crop at 100% pixel enlargement - Unsharpened as well!!
 I am pretty happy with this as neither has been sharpened.  The 5D was at ISO400 and the 7D at 125 (for some reason! - should have been at 100 as I only usually use whole stops, but maybe should have it at 400 for a truer comparison)
5D, 500 + 1.4  - cropped for presentation and sharpened
7D 500, cropped for presentation and sharpened as a direct comparison with the the previous one.
As can be seen from the first two images as the full originals, to get to a useable crop there has been pretty big crops.

Now if we put the 1.4 EFTC on the 500 and 7D, then the subject is much better sized in the frame (obviously) but does mean a lot less pixels are thrown away in the resizing process.

7D, 500f4, 1.4 EFTC, 100% of the image, no crop

And given that the light was good I also added the 2x EFTC, and again at full size, we now have an image that we need to throw away virtually nothing and retain all of the available quality.  Now of course the 2x does compromise IQ  and there are some losses but as we have said before on here, if you have great light, a good steady solid platform and stop down to at least f11 or thereabouts, you can get some good results with it.   In  Live view mode, I also found that the AF still worked with the 7D, and it shouldn't if you read the specs, unless somebody knows otherwise.

Landscape and portrait variants with the 7D, 2 x EFTC and 500 - both full frame

So conclusions!!.  Apart from the ability to pick and choose your reach by virtue of crop, factor, lens length and converter size, I am not particularly sure that I have proved anything  other that that the results are very similar between the 5Dmk2 and the 7D on this particular image.  Does it matter?  For me, not really as I am very pleased that there is this level of consistency and I stress for this type of image.

Clearly what I have shown here is very limited and not really scientific in any way.
But  it did prove, at least to me, that the pixels on the 5D are very good, but then I am not sure that that was ever in any doubt.

Where I will expect to start to see differences will be in the full frame depth of field effects when I start doing a bit of macro work later in the year, and also where the subjects are closer with the longer lenses.
But I like the 5Dmk2 that is for sure, and after the 7D the handling is so similar as to make no significant difference.



  1. Martin

    Really informative comparison, thanks.

    Very close call, but IMHO 5dII has the edge on IQ.

    Obviously this is a static shot, but have you had chance to compare AF speed/accuracy in the real world with BIF, as on paper I read that the 7D's should be more capable for faster moving subjects?

    I realise you chose the 5dII for specific FF benefits, and have the added versatility of the 7D when desired, but as an only body for wildlife would you be inclined to choose the 7D over the 5dII?

    Appreciate your efforts in making this comparison - I'd be pleased with either!

    Kind regards

  2. Hi Julian,

    Agree re IQ, but crop reach is a compromise for teh distant subjects.

    AF performance on the 7D for BIF is fabulous and for all the BIF shots on the same trip (to be posted another time), the 7D was the body of choice. For high speed stuff I have found it to be excellent, and without the 1.4 on the 500, the response is both quick and accurate (although only less so with the 1.4 on)

    For wildlife, if I could have only one body, then it would be the 7D. But for my type of wildlife then having both is the best of both worlds. I expect the 5D to be better when I do my macro work with the 180 as the DOF effects will be much better with the full frame,but mostly because the sensor will be that much closer to the subject. Check out this coming Thursdays post for a short follow up to this one.

    I will do more comparisons soon with closer subjects, and then I will expect to see more differences with FF


  3. Thanks Martin for your reply.
    I understand your logic in choosing the 5DII for the purposes you mention plus noise is much better handled compared to the 7D. I notice the impressive bokeh on the 2010 Naturescapes macro winner was taken with a 5DII 100 f2.8 at 5.6 - your 180 should be even more impressive, and you've got the benefit of Live View which you didn't have with the original 5D for close focus work.
    As you say you now have the "benefit of both worlds" with the 7D and 5DII.