[bobbotron]

I've been having a hard time getting interval shooting to work in my K3 for a while. If I set my camera to the following, it will only take 1 photo (this is in M mode, with 15" second exposures):

Interval: 2"
Number of shots: 6
Star Interval: now

I would expect it to take 6 shots.

If I set it to a large number of exposures, like 115, it seems to chug along, but it's quite odd. Has anyone else seen similar issues? I'd like to get it working solid, I want to get back into star stacking.

[photoptimist]

It's an easy mistake. The "interval" is not the time the camera waits between shots, it's the time it waits between trying to trigger a next shot.

A 2 second interval is like the photographer hitting the shutter button every 2 seconds which does nothing if the camera is still in the middle of a 15 second exposure. A 2 second interval with 115 shots will press the button a 115 time over a 230 second period but if the shutter time is 15 seconds, then there will probably only be about 14 or 15 shots taken.

The interval setting needs to be longer that the shutter time by at least a second or two (longer if you have lots of automagical corrections or a slow SD card).

P.S. if you have slow shutter NR turned on, then you'll want an interval that is twice the shutter time plus a couple of seconds. Slow shutter NR takes the picture and then takes a second dark-frame picture to subtract the sensor noise from the image.

[bobbotron]

Agh, that is confusing. I'm a software developer by trade, this sounds like something I would do before testers remind me of how there's a better way. :P

So if I set the interval to 15 seconds, and my shutter to 15 second exposures... it should take the number of shots equal to the "number of shots" setting?

---------- Post added 12-14-17 at 05:02 PM ----------

Ps, thanks for the help and the tip on the NR setting!

[photoptimist]

Agh, that is confusing. I'm a software developer by trade, this sounds like something I would do before testers remind me of how there's a better way. :P

So if I set the interval to 15 seconds, and my shutter to 15 second exposures... it should take the number of shots equal to the "number of shots" setting?

---------- Post added 12-14-17 at 05:02 PM ----------

Ps, thanks for the help and the tip on the NR setting!

Actually, you might need an interval of maybe 17 seconds for a 15 second shutter time (or maybe 32 seconds if slow-shutter NR is enabled).


Although the system seems stupid, it's the only way to ensure accurate control of the shot spacing which seems to be the whole purpose of intervalometer. And it's the way film camera mechanical intervalometers worked. If you really want EXACTLY 60 pictures per hour for a time lapse, then you don't want the intervalometer measuring time relative to when the camera is ready for the next shot (which varies with shutter speed in P, Av, and Sv modes, in-camera processing, as well as with the complexity of the scene and any thoughtput variations on the SD card). Timing the intervals to the camera's readiness would create uneven intervals.

This is one of those nasty software design situations where both ways are wrong or have nasty unintended consequences that irritate or befuddle the user.

[jbinpg]

Note that in the K-1, the engineers gave us that choice: setting the interval to between actuations or between the end of one exposure to the beginning of the next. They both have their uses.

[Adam]

Agh, that is confusing. I'm a software developer by trade, this sounds like something I would do before testers remind me of how there's a better way. :P

So if I set the interval to 15 seconds, and my shutter to 15 second exposures... it should take the number of shots equal to the "number of shots" setting?

---------- Post added 12-14-17 at 05:02 PM ----------

Ps, thanks for the help and the tip on the NR setting!

A lot of cameras do it that way. Perhaps an artifact of analog intervalometer operation?

If you set the interval to equal the exposure time, the camera will take fewer shots than expected due to overhead in processing. I'd add at least one second in between, preferably two or three. Also, be sure to disable distortion corrections otherwise all the timings will get thrown off more due to the processing time.

[bobbotron]

Thanks for all the help, this is great. I know what's going on now - I shot this last night with this new knowledge, 17" interval, 15" exposure, 140 shots. Here I was considering buying an external intervalometer like a sucker!

[Ian.morgan]

I've always thought that weird too. Thanks for the explanation.