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I want to take repeated long term exposures with the Raspberry Pi. I understand that the maximum exposure time is around 6 seconds. However, taking a 6 second exposure with raspistill takes over 40 seconds. How can I speed this up?

Here is the command and the time it takes to run:

pi@raspberrypi:~ $ time raspistill -w 960 -h 720 -ss 6000000 -o img.jpeg

real    0m43.365s
user    0m0.000s
sys     0m0.020s
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  • Could you post the code you're using to take the long exposures? I'm mostly interested in the capture() call and whether it's using the still or video port.
    – Dave Jones
    May 7, 2016 at 20:42
  • @DaveJones See above.
    – hanno
    May 7, 2016 at 20:50
  • Sorry - completely assumed you were using picamera - you're using raspistill which means it's the still port you're using. Just a mo and I'll grab some info on this...
    – Dave Jones
    May 7, 2016 at 20:53
  • Found it - I'd recommend having a read of picamera ticket #227 to see if that sheds any light on the issue. Basically the answer is to do with the mode switching on the still port, so a video port capture would speed stuff up but would cost you quality
    – Dave Jones
    May 7, 2016 at 20:56
  • But the video port doesn't support 6s exposures. Or am I mistaken?
    – hanno
    May 7, 2016 at 20:57

1 Answer 1

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Thanks to Dave Jones' hints, I was able to get something working with raspivid. In case anyone else is looking for a solution, I use:

raspivid -awb sun -ex night -pf high -ISO 800 -g 1 -qp 10 -ss 6000000 -t 1200000 -b 100000000 -o out.mp4

Which gives this result:

https://youtu.be/8M4zXV36X0c

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