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02-08-2015, 07:26 PM   #1
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Puzzled by Interval Composite

Inspired by the recent article on Composite exposures, I decided it give it a try.
Thus far, though, I'm at a loss to understand the 'interval' part of the setup and am getting
unexpected results.

I have the drive mode set to Interval Composite.
Interval set to 00:00'04" (4 seconds, correct?)
number of shots 240

Exposure, 25 seconds.

Based on those parameters, I would expect the camera to take a 25 second exposure, pause
for 4 seconds, then take another 25 second exposure, pause for 4 seconds, 25 second exposure,
4 second interval....... until 240 exposures have been taken.

What's >actually< happening is: 25 second exposure, 16 second 'interval', 25 second exposure,
16 second interval.......

And to add to the mystery, when I up the shot count to, say, 960, the interval between shots increases
to 22 seconds, even though it's still set to 00:00'04' on the camera.

What am I missing?

02-08-2015, 07:34 PM   #2
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I believe (for predictable behavior) the interval between the shots should be greater than the exposure time of each shot.
02-08-2015, 07:55 PM   #3
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I made the similar mistake before. The timer doesn't know anything bout shutter speed so it just goes off at the set time which is every 4 seconds in your case. At least in my case, if the timer is up and it tries to take a shot, it would just miss that and the total number of shots decreases even though it missed the firing. I'm not sure why you are seeing what you saw. Anyway, if your exposure is 25 seconds, you need to use either 26 or 27 seconds interval (I think K5 only needed 1 second but K3 needs 2).
02-08-2015, 09:01 PM   #4
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Original Poster
Thanks Ruggiex. I noticed something similar. With 240 shots, 25 second exposure and interval 4",
I don't actually get 240 shots, but rather something like 240x4/25. What I can't work out is the long
long interval of 16-22 seconds? Even if the interval counter is clocking while the shutter is open, it
should still only have a 4 second interval, maximum, between shutter close and shutter open.

I have the camera going on another cycle right now: 25 second exposure, 6" interval, 960 shots.
And the interval seems to be in 'scale' this time, ie, about 6 seconds. This will definitely require
thorough testing to understand what's happening when exposure exceeds interval time.

02-08-2015, 09:22 PM   #5
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"Based on those parameters, I would expect the camera to take a 25 second exposure, pause
for 4 seconds, then take another 25 second exposure, pause for 4 seconds, 25 second exposure,
4 second interval....... until 240 exposures have been taken."


using those parameters you need to set your interval to 29 seconds=(exposure + time in between shots)...........240 exposures at that rate will take about 2 hours...btw if you are doin star trails I recommend closing the gap of 4 seconds to 2 seconds as gaps may appear on yer final image and that would be a pity after 2 hours of shooting although it would still make a great time lapse video!
02-09-2015, 04:05 AM   #6
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Quite possibly your camera is taking several seconds (maybe 20 or so) to process the images since they are long exposures, therefore it can't take another until it's ready.
02-09-2015, 06:25 AM   #7
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Is long exposure NR on or off?
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