# Long Exposures on a 5D Mk II



## BHuij (Mar 6, 2013)

Hey everyone

I headed down to southern Utah for a couple of days, and I think it's time to get my starscapes on. I've more or less read up on how to do it, but I have one little worry eating away at me in the back of my mind. How long can/should I go on a long exposure before I need to worry about frying my sensor? I've heard of horrible things happening to CMOS sensors during long exposures; from developing hot pixels in patches to just straight up melting.


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## TCampbell (Mar 6, 2013)

As long as you give the camera a rest after about 10 minutes worth of work you should be fine.  Especially if the temps are cold.  At ISO 1600 I find my star shots don't need to be more than a minute.  The camera should have no problem with that.   But if you shoot an exposure and immediately shoot another, and another, and another, then it could be heating up without having a chance to cool off.  I'd let it take a break ... go study your images, etc. for 5 or 10 minutes while the camera rests before you put it to work again.

If you're attaching the camera to a telescope for deep-space objects then a 60Da or a modified Rebel would be a better body.  My 5D II needs an exposure about 3x longer than 60Da and still the image from the 60Da looks better (the 60Da was designed *specifically* for astrophotography and has a special filter which captures considerably more light in the Ha bandpass which is where a majority of the light comes from in DSOs.)


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