Gaps between subs.

[Matt Scunthorpe]

Hi all,

When i use my DSLR for imaging, i normally set it for 10photos and just hit the shutter button, and it fires off 10 shots with a break in the middle of however long it takes to close the shutter and reopen it. I have just got a remote control that allows me to set up the camera for as many exposures, and length of exposure and gaps in between that i want.

On reading the manual, it says that the gap between each picture should be at least 1 second more than the exposure length. So effectively I'd do a 30second exposure for example, then a 31 second break before the next exposure started and so on.

Is this the way it should be done? Or am i alright to set it for say a 5 second break in the middle. I know its to do with the camera getting too hot etc but i don't want to double the time it takes to do an hours exposure because of breaks in between subs.

Thanks,

[Daddystu]

I tend to have a 30 second break in between my exposures but mine are a bit longer, usually 3-5 mins. Others may have different views but i'd say a 5 second break between 30 second exposures is ok. Maybe 10 seconds.

[laser_jock99]

I've set mine to 20 seconds- not for any particular technical reason- I call it a 'manual intervention interval' so should I wish to put down my cup of tea, run up to the scope and stop the next frame being fired, I have a 20 second gap to get my act together!!

Also some peopled advise a short CCD 'cool down' period between shots.

[lensman57]

Hi all,

When i use my DSLR for imaging, i normally set it for 10photos and just hit the shutter button, and it fires off 10 shots with a break in the middle of however long it takes to close the shutter and reopen it. I have just got a remote control that allows me to set up the camera for as many exposures, and length of exposure and gaps in between that i want.

On reading the manual, it says that the gap between each picture should be at least 1 second more than the exposure length. So effectively I'd do a 30second exposure for example, then a 31 second break before the next exposure started and so on.

Is this the way it should be done? Or am i alright to set it for say a 5 second break in the middle. I know its to do with the camera getting too hot etc but i don't want to double the time it takes to do an hours exposure because of breaks in between subs.

Thanks,

Hi,

I read somewhere that a small gap between exposures is needed allow the chip to cooldown and stablise between exposures, mine is set 15s for 3 ~5 minutes exposure, but I think that the poor Canon is happier with 30s for 2~3 minutes of exposure, 5 minutes is just way too long for an uncooled camera in this heat.

A.G

[Jannis]

On reading the manual, it says that the gap between each picture should be at least 1 second more than the exposure length. So effectively I'd do a 30second exposure for example, then a 31 second break before the next exposure started and so on.

I think this is only so that the camera is able to take the dark-frame before starting on next exposure, and not to cool down the sensor. For "normal" photographing, it's normal to automatically take a dark frame - wich of course have the same exposure as the light frame. This is not needed for astro use, as we take the darks seperatly anyway - so i would ignore the "exposure + 1 sec break" stated there.

Personally i only give my camera like 5-10 sec to cool down between frames, regardless if it's 30s or 300s frames. Never had any problem with sensor heat on the 550d at least.

[Matt Scunthorpe]

Many thanks guys.

I am hoping now that i have the remote i can get upto the dizzy weights of 1minute exposures (dont have guiding etc yet (dont have anymore money )).

[Psychobilly]

I guess you have checked but if you haven't turned of the long exposure noise reduction then the camera will take an auto dark and dark subtract the image before saving it..

I tend to leave 10s gaps between subs to make sure the camera has enough time to write the data to the card and transfer it to the PC...

On the older cams tahat suffered from it, the ampglow would take a number of subs to stabilise and sometime leaving a gap of half the exposure time would keep it "stable"...

Peter...

[Matt Scunthorpe]

I will have to check that tonight. Will it just be in the settings somewhere on the camera? As i dont have a laptop currently, its saving the data to the card, which i then upload to the pc later on.

[Jannis]

It's in the custom fungtions menu on the camera. For astro use, disable "long exposure noise reduction".

[melsky]

I've used my 600D's with exposures up to six minutes and I always set a 1 second gap between frames and have never had a problem, I obviously use the same setting when shooting darks afterwards. I use an Astrotrac and you only get two hours worth of tracking so every second is precious.

Mel

[StuartJPP]

Agree with above...as much integration time as possible. The noise from the sensor getting warm is less than the signal you will get from having twice as many subs...

That is what I believe and do, it may not be correct but I am happy with it.

[Psychobilly]

This is definitely the case 450D and latter... the older Canons and Nikons used to suffer from very "unstable" ampglow and hot pixels...

1000D and later I don't bother with darks as badly matched darks are worse than no darks... I just use lights, bias and flats and let the cosmetic hot and cold pixel removal tools in DSS do their stuff....

Sent from my GT-P7300 using Tapatalk HD

[Twisted Lip]

You know when you read a thread and think, 'maybe I should go check this' lol. i never even really gave this any thought and have always configured to light+1sec just to get things done as quickly as possible. I'll try giving it longer and see what I come up with but really interesting thread on something I'd never really given a second thought to!

[Matt Scunthorpe]

I was the same. Until i read in the instructions and got me thinking.