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Old 12-05-2017, 08:07 AM
jman17
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Wireless remote shutter giving different exposure lengths

Hi,
I recently bought a Promaster wireless Remote Shutter and may be having a problem with it. Even though I have inputted the same exposure times for all exposures it is coming up with often around half of my exposures being a slightly different length than the rest, around one-third of a second or so, sometimes a little more, when I check their lengths on my PC, then Deep Sky Stacker will show 12 seconds for half of them, and 13 for the rest, for example, for what are meant to be 13 second exposures. I have double checked I haven’t put in the wrong exposure length by mistake. Is this normal for a DSLR and this type of intervalometer to do this? I need to know so I can take it back if this is not normal functioning.
Thanks,
jman17
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Old 12-05-2017, 08:20 AM
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iborg (Philip)
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Hi

With my camera (1100D) and a wired intervalometer, I have the camera also doing some dark subtraction (I don't recall what the correct term is), so it takes twice as long to do any given shutter exposure, and then it has to save it all to the card.

So, do you have a suitable time interval set between each exposure?

Whatever you do have set, I suggest increasing the interval by 30sec and see if this helps. It doesn't need to be night, as you are only looking for correct exposure length of the final shot.

Philip
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Old 12-05-2017, 09:10 AM
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ZeroID (Brent)
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Those things aren't particularly accurate in their timing. Just make sure you've got good batteries in it. Give or take a fraction of a second over a long exposure is not an issue..
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Old 12-05-2017, 01:02 PM
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Robert9 (Robert)
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Hi,
There a a few things you must watch. Firstly, how long does your camera take to save the image; secondly, how long does your noise reduction image take (same as exposure length). These times need to be added to calculate the interval time between exposures. Add a few seconds for good measure. Finally, check the batteries in the remote. If you can directly wire the intervalometer to the camera you will soon see if its a battery problem of the remote. Hope this helps. You can check it out without being under the stars; just carry out a sequence of exposures with the lens cap on the camera, then examine the pic details.
Robert
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Old 12-05-2017, 01:29 PM
raymo
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Brent is spot on; I have worked with numerous external intervalometers, [as opposed to camera built in ones], and all display some inaccuracy. As most
AP exposures are at least 15 secs, and usually longer, the inaccuracy is
unimportant[as already stated by Brent]. The main thing to remember to
do when using the in camera noise reduction feature, is to make the interval
at least 30 secs to give some sensor cooling time.
raymo
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Old 16-05-2017, 08:30 AM
jman17
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Thanks

Hi,

Thanks for the advice. My manual recommends an interval time that is 2 seconds longer than my exposure time so I do that and give it 2 seconds between subs, eg 15 seconds exposure and 17 seconds interval. I usually don't use in camera noise reduction.

jman17
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Old 03-09-2017, 05:47 AM
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Astrofriend (Lars)
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Hi,
When I control my camera set to bulbmode from computer or a wired intervallometer it's common the exposure time could be little bit different, parts of a second. It doens't matter normally, but when I use Deep Sky Stacker, DSS I can see it's very sensitive when matching image and dark frames. Sometimes part of second could make it to refuse to calibrate.

If you set the camera in manuell mode you get more precision becuse then it's the cameras own electronics that controll the shutter. But then you are limited to 30 seconds exposures.

As told earlier here, a delay between exposures is good. For me it works with 7 seconds delay, shorter and it could be problem to finished the download to the computer, I I store the imgae on cameras own memory it's faster, but depends on the memory card.

Sometimes i want the pause betweem images be as short as possibly. Then I set the camera shutter to continouos mode. Then just one second delay will be enough. Somthing I use when doing meteorshower hunt. But expect the camera be hot and a little bit more noise.

/Lars
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