1Ds3/7D quick detail check

How sharp are the images from the Canon EOS 7D? I believe there has been some discussion on the matter ;-)

It was suggested (thanks) I take some shots at f/6.3 with the 7D and 1Ds3.

Taking both cameras outside, I picked one of my sharper lenses…

Two views across the street Canon 1Ds3 and Canon 7D

Two views across the street Canon 1Ds3 and Canon 7D

Here are some 100% crops, processed in ACR with no sharpening

Taken with a TS-E90 lens of the view outside of my house, cable release, manually focused with LV x10 ISO100 AV mode

100% crop 1Ds3

100% crop 1Ds3

… and the 7D

7D 100% crop

7D 100% crop

Then I magnified the 1Ds3 image (PS Bicubic smoother) to match the scale of the 7D image.

1Ds3 magnified to match 100% crop of 7D

1Ds3 magnified to match 100% crop of 7D

Of course normally you need to apply some sharpening to any RAW image.

7D image at 100% (sharpened)

7D image at 100% (sharpened)

and finally the scaled 1Ds3 image, sharpened

Sharpened magnified 1Ds3 file

Sharpened magnified 1Ds3 file

Just a quick test, but it confirms what I’d expect – the 7D sensor out-resolves the 1Ds3 sensor with the same lens, it just includes less of the scene.

I’ve made no attempt at optimal sharpening of any image, but it’s enough to show (to my own satisfaction) that the 7D 18MP crop frame sensor  out-resolves the full frame 1Ds3 21MP sensor with a good lens at f/6.3.

When you consider that the equivalent full frame sensor at 7D density is ~45MP, I’m not exactly astounded at the results :-)  Another way of looking at it is that the 1Ds3 is equivalent to under 9MP at 1.6 crop.

Of course this completely ignores the field of view difference. If I used two good lenses at the appropriate focal lengths to match fields of view, then I’d expect the 21MP sensor to provide more detail than the 18MP one. Once you start comparing this though, you are changing a lot more variables…

Note that I’m using the centre of the frame of a good sharp lens – that old kit zoom you saved from the 300D might not be nearly as good as you thought.

As ever YMMV, but I’ve no problem with 7D image sharpness…

  • http://www.northlight-images.co.uk Keith

    This particular test made no attempt to balance exposure exactly between the two cameras. As such I would draw no meaningful information about colour range or quality.

    So far I’ve not seen anything to make me think the 7D is very different – then again I’ve not used it for any jobs where I’d need to make an icc profile. I’ve seen comments from people with a much more ‘exacting’ approach to colour than mine that suggest that the 7D colours might not cover the range – but nothing that I’ve seen for myself.

    I long ago decided that (usually) looking good for an image trumped complete accuracy.

    Sharpening in ACR for the examples above was set at zero – in camera settings are not really relevant, since I’ve not shot a JPEG on the camera since getting it :-)

    I’ve just published some night time shots…

    The night shots do look good, but are very dependent on RAW processing. My impression is that I’m getting at least as good results as if I’d set the 1Ds3 to 3200.

    Of course the higher ISO means that much fewer 7D shots showed camera shake (all hand held)

    The biggest issue for me is not image quality, just the way all my lenses cover so much less field of view (you don’t go to the expense of getting the EF 14 2.8L II if you don’t like using wide angle)

  • Roland

    DO you have a view as to which image represents the more true colours, the 7D image is deeper, bit suspect the 1DS is probably more accurate.

    Also what sharpness setting did you have set? was it zero the default or 2-3.

    Will you do some night photography. my experience between a 5D mark II and the 7D is the 7D pictures look better, you get a lot less streetlight noise in the sky (blacker rather than orange)and teh whites are cleaner. This isn’t what I expected and would welcome a view from someone with more experience

  • http://www.northlight-images.co.uk Keith

    John, I was looking specifically at resolution at a particular focal length, so its the amount of detail in the scene at the same scale I want to see.

    The lower pixel density of the 1Ds3 image means that an x by y pixel 100% crop covers a larger area. Matching it to the scale of the 7D image means up-rezing it.

    The example would be taking a picture of a distant small bird with say a 400mm lens. On either camera the image of the bird on the sensor covers the same area. On the 7D there are more pixels in this area, so assuming it’s a good lens, there will be more detail in the shot. I’m assuming here that the bird fits within the frame of the crop camera.

    Given the difference in pixel density between the two cameras, this was exactly what I’d expect to see. Fortunately the TS-E90 is more than sharp enough to show the difference, so you do see it.

    If however I was looking at different lenses that gave the same FOV for each camera, then the more MP of the full frame camera would trump the crop camera.

  • John

    Wouldn’t a better test have been to downsample the 1Ds3 image?

    Oh. And the kit lens I saved from my 300D? Just exactly not nearly as good as I thought.

  • http://www.akbarfoto.com akbarfoto

    great review! something that used in real world. comparing with and without sharpening, plus the variable that I’m looking for. I mean, it is hard comparing two cameras with different size of sensor.