Overall Image Quality / Specifics

From all our testing and evaluation so far it's fairly clear that the EOS 5Ds sensor has very similar characteristics to the EOS 20D (pixel for pixel), considering how highly we rate the EOS 20D that alone would be a good enough reason to want this camera. Resolution is excellent, as expected, the EOS 5D is capable of extracting detail down to its absolute limit (some subtle moire). The larger pixel pitch means that the sensor requires less resolution from the lens than a smaller sensor, on the flip side however a full size sensor does mean you get to see the edges of the lens, lens shading, softness and CA at times. That said you really only need worry with wide angle lenses and larger apertures.

I'll be honest and say that when I started using the EOS 5D I wasn't a big fan of Picture Styles, but they have grown on me. The Landscape setting is the best way to get vibrant 'natural looking' foliage green and deep blue skies. I only wish Canon had gone a little easier on the sharpening, I turned it down to level 2 for both Standard and Landscape Picture Styles (if you don't do this you risk strong halo sharpening artifacts around detail).

Nobody comes close to Canon for low noise at high sensitivities (ISO), their breakthrough CMOS sensor continues to rule the roost in this respect. The EOS 5D can deliver amazingly clean images even at ISO 1600, you can switch the camera into this high sensitivity setting comfortable that the images you get are going to be so clean they would be difficult to distinguish from ISO 400 images from other cameras. One small difference we did observe is that the EOS 5D appears to use more noise reduction at high sensitivities compared to the EOS-1D series, which are tuned to maintain detail rather than have it softened by NR.

Lenses in focus: Edge softness / chromatic aberrations

As we explored earlier in this review and have discussed in previous 'full frame' digital SLR reviews such big sensors expose the weakest part of all lenses, the edges and corners. These limits occur most often at extreme wide angle and/or large apertures (even with the most expensive professional 'L' lenses). The samples below were from the same 17-35 mm lens. On the counter side we should also say that the field of view provided by (say) a 17 mm lens on the EOS 5D would be difficult to achieve on a cropped sensor camera.

EF 17-35 mm F2.8L @ 25 mm, F9 EF 17-35 mm F2.8L @ 17 mm, F4
Edge crop (100%) Edge crop (100%)
Center crop (100%) Center crop (100%)

* Note that if you are shooting in RAW it is possible to (mostly) remove edge/corner chromatic aberrations using Adobe Camera RAW

AI Servo interference banding

Credit for the discovery of this particular issue must go to our discussion forums. Quite a few early adopters there noted that when using certain lenses at high sensitivities in AI Servo (continuous auto focus) mode banding interference artifacts can be seen, most clearly in shadow areas. This appears to be some kind of radio frequency or electrical interference from the auto focus motor. Obviously this is a fairly specific issue which would only be an issue if you do a lot of continuous auto focus shooting with certain lenses.

EF 50 mm F1.4, ISO 1600 EF 50 mm F1.4, ISO 3200
50% crop 50% crop