Three modes of continuous shooting

[danielfrimley]

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On my CL, the fast and medium continuous shooting modes are smooth and consistent with a very regular interval, whereas the slow mode seems to stumble along a bit.

 

The instruction manual indicates that fast mode is up to 10fps (I haven't timed it but have no reason to question it) but nothing about the frame rate on the slower two modes. In itself that doesn't concern me but I do worry a bit that slow mode (only) seems irregular. It may take 3 shots, pause, take 4, pause, run off a couple of quick ones, pause, run 7 or n more without pause and so on and so on in no particular order - it stutters basically.

 

I am using extended shutter and EVF, AFs and auto review off.

 

Can anyone replicate this behaviour? Is it expected.

[scott kirkpatrick]

A good way to look at continuous shutter timing is to photograph a computer screen with an online stopwatch counting up the time, e.g. www.online-stopwatch.com .  With the camera on a tripod or holding it while resting comfortably, you can let her rip and see what times appear in the images.  Since the screen refreshes maybe 60 to 80 times a second and the program may miss a refresh now and then, and "stopwatch" shows time to .001 sec, the times shown are good to a bit under 0.1 sec.

 

With a mechanical shutter I have heard a stutter sound to the continuous shutter on the SL before, but haven't tried it before on the CL.  One or two erratic shutter times are common when you just start up.  This time I used MF, full time electronic shutter.  High speed went nicely at 10 frames per second until I had shot about 33 frames, and then began to miss groups of 2-4 frames as the buffer filled up and writing to the chip interfered with shooting.  Medium speed stayed at five frames per second for about 7 seconds with one or two gaps where  there were only 4 shots in a second.  Looking at the intervals, it seems that it misses a shot every few seconds.  So my medium speed wasn't quite smooth.  With the slow speed, there were a few initial shots with slightly erratic intervals, but then it settled down to very consistent half-second intervals, which it kept up without deviation for 20 seconds.  So the slow continuous shooting doesn't fill buffers, and if it doesn't have to coordinate with the mechanical shutter, is quite smooth.  Results with the mechanical shutter may be different from my results with purely electronic shutter, so try this experiment in the way you will be working.

[danielfrimley]

A good way to look at continuous shutter timing is to photograph a computer screen with an online stopwatch counting up the time, e.g. www.online-stopwatch.com . With the camera on a tripod or holding it while resting comfortably, you can let her rip and see what times appear in the images. Since the screen refreshes maybe 60 to 80 times a second and the program may miss a refresh now and then, and "stopwatch" shows time to .001 sec, the times shown are good to a bit under 0.1 sec.

 

With a mechanical shutter I have heard a stutter sound to the continuous shutter on the SL before, but haven't tried it before on the CL. One or two erratic shutter times are common when you just start up. This time I used MF, full time electronic shutter. High speed went nicely at 10 frames per second until I had shot about 33 frames, and then began to miss groups of 2-4 frames as the buffer filled up and writing to the chip interfered with shooting. Medium speed stayed at five frames per second for about 7 seconds with one or two gaps where there were only 4 shots in a second. Looking at the intervals, it seems that it misses a shot every few seconds. So my medium speed wasn't quite smooth. With the slow speed, there were a few initial shots with slightly erratic intervals, but then it settled down to very consistent half-second intervals, which it kept up without deviation for 20 seconds. So the slow continuous shooting doesn't fill buffers, and if it doesn't have to coordinate with the mechanical shutter, is quite smooth. Results with the mechanical shutter may be different from my results with purely electronic shutter, so try this experiment in the way you will be working.

May I ask which SD card type you used for your tests? I have yet to evidence it though anecdotally (and counter intuitively for me) the problem is exacerbated when I put a Lexar UHS-2 in the camera.

[scott kirkpatrick]

May I ask which SD card type you used for your tests? I have yet to evidence it though anecdotally (and counter intuitively for me) the problem is exacerbated when I put a Lexar UHS-2 in the camera.

I was using a Hoodman 2000X UHS-II.  The type of card will certainly make a difference.  There are at least three quasi real-time programs running here, each doing I/O.  The camera writes each image to the buffer for processing, another program in the camera writes the processed image to the card.  Interaction with the mechanical shutter controls may add another real-time operation.  And the stopwatch program is writing a time which it can calculate to better than a millisecond to a display which allows it to write at most every 1/50 to 1/100 of a second.  Yet the shooting rate, averaged over a second or so, is nicely 10, 5, or 2 per second.  Listening to the mechanical shutter, we can tell that on a scale of perhaps 1/20 of a second, it is less smooth.  So if you want to do the Gjon Mili sort of golf swing multi image with the golf club moving smoothly from shot to shot, I would use the fastest speed and start shooting before the swing starts to get into a smooth pattern.

Edited June 14, 2018 by scott kirkpatrick

[danielfrimley]

I was using a Hoodman 2000X UHS-II. The type of card will certainly make a difference. There are at least three quasi real-time programs running here, each doing I/O. The camera writes each image to the buffer for processing, another program in the camera writes the processed image to the card. Interaction with the mechanical shutter controls may add another real-time operation. And the stopwatch program is writing a time which it can calculate to better than a millisecond to a display which allows it to write at most every 1/50 to 1/100 of a second. Yet the shooting rate, averaged over a second or so, is nicely 10, 5, or 2 per second. Listening to the mechanical shutter, we can tell that on a scale of perhaps 1/20 of a second, it is less smooth. So if you want to do the Gjon Mili sort of golf swing multi image with the golf club moving smoothly from shot to shot, I would use the fastest speed and start shooting before the swing starts to get into a smooth pattern.

This is really helpful thank you. I believe I've narrowed it down to the card. When I use a SanDisk Extreme UHS-1 (90 read, 30-40 write) I can use slow drive mode for between 7 and 13 regular intervals every time before things start caching/ writing/ queuing and irregularity kicks in (as one might expect considering the card spec) - If I use the Lexar 64GB 2000x Professional UHS-2 card it's all over the place straight off the bat. The CL's UHS-2 support is documented and clearly working or there'd be forum posts aplenty so I'm sure it's either the brand or the card itself.

 

Now I think of it, I've managed to freeze/ lock up the camera with the drive read-write light on steady when reviewing images on the LCD a few times - that's only ever happened with the Lexar.

Edited June 14, 2018 by danielfrimley