I’m going to be doing some synthetic slit scans with the Sony a7RII, and I needed to figure out what frame rate the camera could sustain on a continuous basis, so I did some testing. Thinking that others might be interested in the results, I’m sharing them here.
Test conditions
- Sony a7RII
- Lexar Professional 1000X (150 MB/s) 256 GB SD card
- Silent shutter on (as it turns out, this doesn’t make any difference).
- ISO 100 (no noise reduction)
- 1/500 second (no noise reduction)
- Manual exposure mode
- Manual focus mode
- Single shot shutter mode
- Autoreview off
- Nikon 200/2G VR I lens
- Vello smart adapter
- Sony AC power supply
- JJC wired intervalometer
The results
- Full Frame, Raw, uncompressed: 4 seconds between exposures is the fastest rate with no missed exposures
- Full Frame, Raw, compressed: 3 seconds
- Full Frame, JPEG, Extra Fine: 2 seconds
- Full Frame, JPEG, Fine: 2 seconds
- APS-C, Raw, uncompressed: 2 seconds
- APS-C, Raw, compressed: 2 seconds
- APS-C, JPEG, Extra Fine: 2 seconds
- APS-C, JPEG, Fine: 1 second
Notes
The intervalometer’s setting precision is 1 second, so in some cases, the camera can easily obtain the rates above, and on others it can barely get there. For large file sizes, the camera appears to be limited by the speed with which it can write to the SD card. The maximum write speed of the card I used is substantially above the a7RII’s USB-2 write speed, so any fast card should yield the same results.
[Added 10/17: I’ve been asked how many shots until the first miss with full-frame, compressed raw.
- 1 second gets you 102 shots.
- 2 second gets you 243 shots.
These numbers aren’t particularly repeatable.]
I did the testing with a Vello adapter and a Nikon 200/2 VRI lens. I noticed that silent shutter didn’t mean silent operation. I listened closely and discovered that the diaphragm stopping down on the Nikon 200/2 makes a fair amount of noise. I’d never noticed that before, since, when used with a DSLR or with the a7x cameras in EFCS mode, the sound of the lens is masked by the sound of the camera’ shutter.
Huh. Useful info for the more mundane purpose of time lapse…thanks.
Hi Jim
I’ve noticed that by default leaving a comment results in an email asking you to confirm that you want an email update about further comments. While that’s much better than just auto updating, it would be better still if there was a check box when you leave a comment that opts out of ‘subscribing’
David, thanks for telling me about that. It must have gotten broken as part of the change in themes. I think it’s fixed now.
But you have to take in mind that the SD card slot of this camera is UHS-I only which means that the card you were using can write half of its speed tops. 150mb/s will get under 75mb/s.
That is very likely a big component of the explanation for why the camera behaves the way it does. There is a point, and it arrives pretty soon these days, where you are wasting your money to buy fast flash cards with these cameras. I buy them anyway, in hope of improvements in the near future.
The UHS-I standard is physically different therefore I doubt that there will be improvement with UHS-II cards. The best card for you will be Sandisk UHS-I the fastest model. I Like Samsung cards but Sony did not add them in the firmware maybe and I can not write 4K 100mbit on them despite that they are way over the needed speeds for the job. Sony Sd cards are crap :), I have one and the camera behaves strangely with it and not only A7rII, the A7r and A6300 did that too.
I meant with the next-generation alpha cameras.
Ooo I am hoping that there will be two UHS-II card slots 🙂