Just how is the rolling shutter exactly on the A7S – intolerable or similar to what we’re used to on other DSLRs?
Samuel H has added the A7S to his rolling shutter scores sheet over on the DVXUser forum. The time it takes to scan the sensor from top to bottom is calculated by more than one user and an average figure produced. This helps to put a number on the issue and to compare the A7S to other cameras. Here are the results.
- GH4 1080p (Micro Four Thirds): 13.7 ms
- Scarlet (4K) 14 ms *
- RX10 (1″ sensor): 14.8 ms
- GH3 (Micro Four Thirds): 15.5 ms
- C300 (4K sensor, 1080p image) 16 ms
- BMPCC (Super 16mm): 17.8 ms
- A7S (APS-C crop mode 1080p): 19.5 ms
- 5D Mark III (full frame): 20.5 ms
- 7D (APS-C, 1080p): 21ms *
- D5200 (APS-C): 22.4 ms
- GH4 (4K, 2.3x crop): 22.5 ms
- GH1 (1080p, 2.0x crop) 25 ms *
- BMCC (2.5K, 2.3x crop): 25.0 ms
- 5D Mark II (full frame): 25.9 ms
- NEX-5N (APS-C): 29.4 ms
- A7S (1080p, full frame): 30.5 ms
* Not verified
A7S is ranked below the BMCC, 5D Mark II and NEX 5N at the foot of the list unfortunately.
Though the scores are for 1080p there’s no reason to think it will be even worse in 4K mode as the sensor is already outputting all pixels in 1080p mode anyway.
(End of update)
Rolling shutter is just about the one thing Sony seem to be separating the A7S’s image quality from their pro line of cameras. That and the lack of 10bit internal 4K recording that is.
So far I am absolutely in love with the image coming from the A7S, from what I have seen put online so far.
This is one of the best rolling shutter tests I’ve seen so far. Not only are the traditional train shots present… We have lightning too! 🙂
It really does give you an accurate impression of the problems of handheld shooting and rolling shutter on the A7S.
So what’s the solution?
Well a change of shooting style is one obvious solution. Rolling shutter is not a shot breaker for everything and sometimes when it is IS there, you don’t always notice it.
It’s also something which can be fixed in post. Premiere Pro CC has a rolling shutter fix tool which removes it altogether but introduces a crop to the image. However since the A7S is 4K externally and full frame you have plenty of sensor area and resolution to sacrifice in that crop. Even if it crops to 1.3x that is still 1D C / APS-H rendering of your lens and greater than 3K resolution.
This is very good news as on a small sensor, or with 1080p, a crop is not really very tolerable. In 4K on full frame, it is.
At this moment in time, we’ll just have to put up with rolling shutter. It is a necessary consequence of having 4K and a full sensor readout. Much more data to read out from the sensor in a single scan. Any faster and the camera would overheat. The upside is that what we gain from the full pixel readout and 4K is much more of a benefit than the negative of the skew, which is fixable in post anyway.