DxOMark has just announced the results of their sensor tests of the new Micro Four Thirds flagship camera – the Olympus OM-D E-M1 Mark II and for a cropped sensor it performs superbly and remarkably, the overall sensor image quality score is comparable to the new Nikon D500 cropped sensor dSLR and the Canon 6D and Canon 5D Mark III full frame dSLRs!
Now that is a pretty good achievement indeed and further lessens the need for a big, heavy, expensive dSLR kit, especially when there is far more to the camera than just the sensor – it’s feature set just blows the Canon 6D and 5D Mark III dSLRs away with its in-built 5.5EV image stabiliser that works on all lenses and even becomes 6.5EV effectiveness with the Olympus OIS lenses, its 50mp sensor shift HiRes mode, ability to accurately focus on the subject’s closest eye no matter where they are in the frame, up to 60fps burst rate, up to 1/32,000th sec shutter, Live Composite mode for night imagery, 4K video with awesome image stabilisation, and much more.
How did it score?
Overall score of 80 beats the E-M1 mark I’s score of 73, and almost matches the Nikon D500’s score of 84 (wins on dynamic range but similar image noise), and is comparable to the Canon 6D score of 82 and the Canon 5D Mark III’s score of 81 – the Canons winning on image noise but losing significantly on dynamic range – see side by side comparisons on DxOMark here.
First the bad news – the ISO issue.
For some reason, perhaps a marketing con, Olympus appears to have incorrectly assigned the ISO levels as the measured ISO as per DxOMark tests is consistently just over 1EV lower than stated.
For most people this will not be an issue, but if one is using manual exposure settings from another camera, or from an external light meter, then users may need to make an adjustment, and if one is comparing image quality at same ISO settings between brands, this needs to be factored in – as they have on DxOMark’s analysis which take this issue into account.
Strangely, the LOW extended ISO setting of ISO 64 was measured at ISO 83 which was the same measurement for the base ISO setting of 200!! This suggests there is NO real benefit of using the LOW setting at all!
This has tended to be an issue with most Olympus digital cameras including the E-M1 mark I but to a lesser extent.
But there is a lot of good news!
Image noise is significantly improved over the mark I with an almost 1EV improvement, and other tests of the mark II also show an incredible result with thermal sensor noise at long exposures.
That said, predictably, image noise still falls 1-1.5EV short of the image noise on contemporary full frame cameras, but for most of us, the level of image noise is not really an issue unless we need to shoot above ISO 1600 which is quite rare (>90% of my shooting is at ISO 200-400).
Shooting at high ISO levels even on full frame cameras is not a great idea unless you really need to as not only do you get increased image noise but, more importantly, you lose dynamic range – for the Canon 6D and 5D Mark III you lose 1 EV dynamic range at ISO 1600 compared to ISO 200, and these cameras have limited dynamic range to start with.
The only time the full frame image noise really has a substantial advantage is in some types of shooting moving subjects in low light or in Milky Way astroscapes.
If you need a certain amount of depth of field in your low light images, then, the full frame noise advantage may be nullified as the E-M1 can resort to 2 stops wider aperture to achieve that depth of field and this means 2 stops lower ISO.
If your subject is static, the E-M1 Mark II wins again thanks to its far better image stabilisation and electronic shutter capabilities.
Dynamic range is the ability to capture are large range of scene brightness levels, the greater the dynamic range, the less likely you will get blown highlights in which you lose image detail totally and which cannot be readily addressed in post processing.
In many respects, dynamic range is more important than high ISO image noise because it will affect every image you take no matter what ISO.
At ISO settings of 200-400, the E-M1 mark I had better dynamic range than the Canon 6D and Canon 5D Mark III, and now the E-M1 Mark II extends that gap a little so that it is 1EV better than the 5D Mark III and 0.6EV better than the Canon 6D and 0.4EV better than the newer, and very expensive, Canon 5DS / 5DSR full frame dSLRs!
New full frame cameras such as the Canon 5D Mark IV and Nikon D750 generally have a better dynamic range than E-M1 Mark II.
Keep your ISO at 200-400 and be happy that your sensor image quality will surpass even a Canon 6D, 5D Mark III, and in HiRes mode will presumably better the 50mp Canon 5DS / 5DSR.