Dpreview today has put out their studio scene with the EOS R6 Mark III, which gives us our first side-by-side look at how the EOS R6 Mark III compares to its relatives and also its competitors. One thing about sensor design is that there is no such thing as a free lunch. Something has to give if you want to increase the sensor readout speed, and usually, the cost is slightly lower image quality. Now when it comes to read out speed, even though the numbers look good when compared to their competitors, we should note that at times Canon can now be firmly in the “we’re cheating a bit” or in this case, 2 bits, as Canon usually offers on it’s none stacked sensors, 12 bit readout with electronic shutter for both stills and video. Canon uses a ramp comparator. The last time I’ve seen their sensor patents discuss their AD on sensor chip, and this means the more precise you want the measurement, the more time it takes to make that measurement, which is why Canon limits the amount of bits in the faster readouts. Do keep in mind that when comparing the EOS R6 Mark III to the EOS R6, the EOS R6 Mark II, or the Nikon Z6 III, numbers do have a quality of their own. At the same time, dpreview shows a downsampling of the image to equalize the resolutions. You can take more pixels in the R6 Mark III and use far more advanced tools to reduce its noise, and you have 40% more pixels to work with to do so. Dynamic Range / Exposure Latitude According to dpreview’s exposure latitude test charts, which are meant to see how much you can push an image up in terms of exposure to see where it starts to fall apart with noise. We will look at the EOS R6 Mark III as compared to the EOS R6, EOS R6 Mark II, and the Z6 III, which I think is a good choice because it has similar prioritization to the R6 Mark III. When looking at a heavy push, but not the most extreme for dpreview’s test scenario, it appears that the difference in DR is less than 1 EV, with the EOS R6 Mark II having the better latitude. The EOS R6 Mark III looks very similar to the response you’d get out of the Z6 III with its partially stacked sensor. The EOS R6 Mark III also appears to sit right in between the EOS R6 and the EOS R6 Mark II. There’s really not much to differentiate the four cameras. If we look at a more dramatic push, oddly enough we see that the Z6 III and the original R6 fall off the cliff in terms of noise in the shadows, while the EOS R6 Mark III is just slightly more noise than the EOS R6 Mark II. There’s a difference, but it’s pretty slight. Now, where the Nikon Z6 III cleans the EOS R6 Mark III’s clock is when you switch the EOS R6 Mark III to electronic shutter and compare the results. Here we can see the effect of the R6 lineup using 12-bit, with the Z6 III a good 1 EV better in the shadows on a hard push of +6EV. So in short. The Internet forums will now be filled with “I cannot shoot without an electronic shutter, and I need maximum dynamic range. My photography extreme skills require this. This camera is dead to me” because that’s the way the internet rolls. I kid, I know there are certain use cases where an electronic shutter and high dynamic range are indeed useful, so don’t go that crazy on me in the forums 😉 High ISO Noise High ISO noise is much trickier to see the difference unless you start to hit the end of the ISO ranges of these cameras; they are all just that good. There’s maybe a bit more noise at ISO 12, 8000 than the others, but it’s close enough that it would be difficult to see the difference in practical terms because you have more pixels able to reduce noise better. At around ISO 51, 200, the other cameras do pull away from the EOS R6 Mark III, but it’s less than one full stop difference in high ISO noise. There’s really not much to separate the cameras here. Closing Thoughts The EOS R6 Mark III delivers excellent results, but the decrease in rolling shutter by increasing the readout speed does come with a slight amount of cost. Canon increased the pixel count significantly from the other cameras that we are comparing against. When you consider this, they increased the resolution and still made a sensor that was quicker to read out than the EOS R6 and EOS R6 Mark II. All things being equal, the sensor has to read 4640 lines instead of 4000, and it’s still quicker. Canon even managed to get a readout speed faster than the Nikon Z6 III’s partially stacked sensor. It’s even worse if you consider that Canon is DPAF, so in theory, if you are comparing it against the Z6 III, Canon is reading 4640 lines of 13920 columns, instead of the Z6 III’s 4000 lines and 6000 columns. ISO ranges, such as what we’ve talked about, are also dependent on the sensor temperature at the time of shooting and the overall camera temperature. This is directly influenced by how long you’ve been using it, since the sensor runs all the time in a mirrorless camera. So if Canon has improved the cooling of the camera between successive models, it could be that after prolonged use, the EOS R6 Mark III may actually deliver superior results to its EOS R6 and EOS R6 Mark II predecessors. However, in practical terms, unless you continually photograph in the upper boundaries of the ISO range or sensor dynamic range, the differences are not vast, and in practical terms and you most likely will not notice it.
https://www.canonrumors.com/canon-r6-mark-iii-high-iso-and-dynamic-range-good-but-not-class-leading/
Canon R6 Mark III High ISO and Dynamic Range – Good, but not Class Leading
