The key question with the 5DS R is simple: does having all those pixels pay off? The answer is yes, but with some caveats.
A pixel count this high starts seriously pushing the extremes of lens performance, and optical aberrations are described in merciless detail. To make the most of the sensor resolution, you’ll therefore need to use top-quality optics. Canon says that all the lenses it has released since 2010 have been designed with high-resolution sensors in mind, but older lenses can also give fine results – especially primes (including the sub-£100 50mm f/1.8 II). But it’s also crucial to understand that the 5DS R will get better results out of any lens that you use on it than any previous Canon DSLR. Careful image processing is essential to maximise the final image quality, and with most lenses you’ll need to correct chromatic aberration as a matter of course.
Impeccable shooting technique is also necessary to avoid blur from camera or subject movement. This means using either a tripod or high shutter speeds when shooting handheld. Forget the 1/focal length rule for safe handholdable speeds, and shoot a couple of stops faster, for instance 1/200sec with a 50mm lens. You’ll also need to use optimum apertures to get the sharpest results, usually f/5.6-f/8. If you need to boost the ISO to achieve this, that’s just the price that needs to be paid. The sensor behaves very well up to ISO 1,600 at least, so there’s some leeway for pushing things a bit.
The EOS 5DS R’s files are huge, so large fast cards are essential – don’t think you’ll get away with recycling CompactFlash cards bought five years ago. Raw files typically weigh in at 60-70MB, meaning that a 32GB card is good for about 320 shots in raw + JPEG. Processing these files will also place a huge strain on your computer’s resources so major upgrades may be in order.
Viewing the 5DS R’s files on the computer, though, is a revelation. At its best, the camera is capable of recording jaw-dropping levels of detail (in context, its 8688×5792-pixel resolution equates to a 29x19in/74x49cm print at a critically sharp 300ppi output resolution). Canon’s new ‘fine detail’ picture style does what it claims, and incorporates pretty much all the detail captured by the sensor into the camera’s JPEGs. This is a huge improvement over the 5D Mark III, which has a bad habit of sacrificing fine detail to over-enthusiastic noise reduction.
I shot almost invariably using evaluative metering, and found that it performed exceptionally well, and generally did an excellent job of avoiding clipping highlights. Naturally spot and partial metering modes are on hand for difficult situations that might confuse the metering.
One area where Canon has tended to lag behind other brands is low ISO dynamic range. Fortunately, the 5DS R’s sensor seems to be improved in this respect, allowing perhaps 3 stops of additional shadow detail to be recovered before noise becomes a problem. You can see this in the example above, where I applied extreme exposure and highlight/shadow adjustments to bring out more detail. This isn’t quite a match for the extreme shadow detail recovery that’s possible from the Nikon D810, but it’s still pretty useful in high-contrast conditions.