Is it possible to shoot in intervals below 1 second?

[Tangibledan]

Hi All,

I have a very specific requirement, I need to continuously shoot full frame RAW for 1 minute and capture as many frames as possible. Burst mode will capture compressed RAW at 10 FPS but for 68 frames. Interval mode is only every 1 second. I'm looking for something better than this, does anyone know of software/firmware which can get my shooting up to say 5FPS continuous for 60 seconds? 

Camera: Sony ilce-7rm4

Many thanks for your input.

Dan

 

[dbmiller]

A couple things to try. You are basically limited by:

1. How fast the camera can write to the card
2. How many frames per second you are shooting at
3. How big the camera buffer is

You can't do anything about item #3, so let's look at the first two.

1. Make sure you are using a fast UHS-ii card. If you are using both slots, make sure both cards are fast - The camera writes to both cards at the same time, but will not start the next image until both cards are written. The R4 supports UHS-ii in both slots, so you should be good as long as you are using fast cards. Once that image is written to both cards (or the one, if you only have one card), that buffer space is free to hold another image in the queue to be written. I don't know the speed that the R4 can achieve, but most test results I've seen say the Sony cameras underperform in this area, and aren't able to write at the full write speed that the cards say they can. Make sure the card is freshly formatted in camera for best results.
2. The R4 can shoot at different frame rates in burst mode. Hi+ = 10fps, Hi = 8fps, Med = 6fps, Low = 3fps. So shooting in Low burst mode should last over 3x longer than Hi+ mode. The R4 files are huge, so another option might be to shoot in APS-C mode, where each image is only 26 megapixels instead of 60. That could increase the number of images you can take by another factor of 3x.

[Chrissie]

9 hours ago, dbmiller said:

The R4 can shoot at different frame rates in burst mode. Hi+ = 10fps, Hi = 8fps, Med = 6fps, Low = 3fps. So shooting in Low burst mode should last over 3x longer than Hi+ mode.

I mostly agree to what you're saying, but would like to add a little refinement to the above quoted statement:

The camera contains a high-speed buffer of limited size. "High-speed" refers to the speed, at which can be written into that buffer.

The buffer can be drained only at a - say - traditional speed, i.e. slower. That's why the buffer eventually fills up, at which point the burst frame rate will fall back to what the write speed of your memory card sustains.

The point is, that this high-speed buffer can be filled and drained simultaneously, with the fill rate being higher than the drain rate.

Suppose, the drain rate was 2fps (a wild and unsubstantiated guess), then filling it at 10fps would give you a net fill rate of 10-2=8fps.

While filling the same high-speed buffer at 3fps would result in a net fill rate of 3-2=1fps. So that would make for an eightfold* difference in net fill rate.

* : based on wild guess

That said:

I'm using this wireless remote trigger, which supports most everything you might ever want to do, like single shot, high speed/low speed burst of between 1 and 99 shots (of infinite number of shots), delayed shots, timed shots.

  

[Tangibledan]

dbmiller and Chrisse, 

Thank you for the quality replies, I wasn't aware that I could set the frame rate on the Burst mode, very useful, thanks for that. Also the wireless remote trigger could solve the problem on the interval timer, if say I can set a sustained burst of 5fps and the memory cards can sustain that for 1 minute, and the camera doesn't overtheat. But it's London in November so at least ambient temps are on my side

 

Cheers

 

[dbmiller]

Agreeing with Chrissie here, as we are sort of saying the same thing, but I didn't perhaps get fully there. Chrissie is correct in that what you are really concerned about is the fill rate - Once the buffer is full, the camera won't take another image until one is written to the card, so you're really worried about how fast the buffer fills vis-a-vis the FPS input rate and the output rate based on the write speed of the card.

As the camera starts writing immediately, you will certainly be able to get more than a buffer full of images (68 on the R4?) before the buffer is actually full. I didn't time this video, but here's an example of someone using a high speed card at 10FPS in the R4, and a comparison with the R3. He also does it in crop mode, so you can see the difference. He doesn't change the FPS, and only has one card slot in use. Definitely take longer than 7 seconds to fill the R4's buffer, probably at least twice that, maybe more.