By site editor Dan Chung:
So far in my testing of the a7R II I have been impressed with its resolution and handling. But these aren’t the only characteristics that matter to real world shooters.
During my pre-release testing of the a7R II I observed that the rolling shutter or ‘jello’ effect when shooting 4K was quite strong in the S35 crop mode, but much improved in full frame mode. In those early tests I wasn’t able to publish video from the pre-production camera. Now that the release version is in my hands I’ve been able to record some quick tests that show the performance of the two modes, and also compare it with its two leading competitors – the a7S and the Panasonic GH4.
This isn’t a lab test but even so I tried to make conditions as identical as possible. I took the a7R II and stacked the other camera directly on top of it, then put the two onto a Sachtler Video 18 tripod. A 70-200mm lens was put on each camera and the lenses were set to match the magnifications between the different modes. Shutter speed was set to 1/50th on each camera and the aperture was f4 on both setups. A variable ND was used to match exposures as closely as possible.
As an aside, this test proved to me just how difficult it is to test the image quality differences between cameras that have different crop factor and differing base ISOs. The differences in colour and softness caused by neutral density filters, lenses at different apertures and different codecs can makes fair comparisons hard. For these reasons this test should not be used to assess anything other than rolling shutter.
Internal recording was used on all three cameras at the highest resolution and bitrate that each permitted. Obviously you would never actually shoot a shot this way in an actual production, but it makes for an interesting comparison nonetheless.
The results re-affirmed to me what I knew from my earlier tests. The jello effect is pretty bad when the camera is set in S35 mode. It is very similar to the performance of the sister a7S in full frame mode. For fast moving subjects and sports this could be a real problem.
Luckily if you switch to full frame mode its a different story. The rolling shutter is much reduced. How much? well it is very close to the M4/3 sensor of the GH4. This comes as quite a surprise as the GH4 sensor is much smaller. Obviously Sony have some clever stuff going on here that allows the full frame sensor to scan the image so quickly.
In my previous testing I found the image quality of the full frame mode to be quite good, with less aliasing and moire than I expected. I would recommend anyone using the a7R II for fast moving subjects to try using this mode in the first instance.
Stay tuned for more tests soon.