# Sensor 'Burnout'



## PhilGarber (Oct 4, 2008)

Hey all,

What is 'sensor burnout? I've heard it can happen by leaving your shutter open to long, but how long is 'too long'?

Thanks,

Phil


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## ann (Oct 4, 2008)

sometimes with long exposurers individual pixels "die" leaving small colors on the image, which can be fixed with an editing program.

as to what is too long, i know of a photographer who took up to 30 minute exposure with no ill effects to the sensor.

i have taken up to 15 sec. exposures, on occassion i have had a "hot spot" but nothing too worry  about.


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## PhilGarber (Oct 4, 2008)

How long do you think a rebel xt could stand?


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## Garbz (Oct 5, 2008)

Ann he's not talking about dead pixels, he's talking about a dead sensor.

When I picked up my lens from a camera repair shot I saw a Canon 350D with a dead sensor. The owner did a 40min exposure. Not sure when in the process it died, it may even have failed during noise reduction afterwards. Either way it's a big risk and there's no easy number to stay away from. I have also seen a wonderful 45min startrail shot, noisy as heck but also done on a still working 350D.

I have done a 1 hour exposure on my D200 but the image was totally useless. Purple bleeding over the entire frame and the number of dead pixels were as high as several percent. There's quite a few threads current here where people are asking what the purple bleeding is after taking only a 15 minute exposure. Also long exposure NR sometimes totally fouls this up making the rest of the image green.

I assume you're trying to do star-trails? Try a stacking technique http://www.tawbaware.com/imgstack.htm. The many short intermittent breaks during exposure will reduce heat (but sensor burnout would still probably be an issue so take care). The various frames also cause the sensor to reset eliminating the purple bleeding.


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## ann (Oct 5, 2008)

sorry


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## PhilGarber (Oct 5, 2008)

Garbz said:


> Ann he's not talking about dead pixels, he's talking about a dead sensor.
> 
> When I picked up my lens from a camera repair shot I saw a Canon 350D with a dead sensor. The owner did a 40min exposure. Not sure when in the process it died, it may even have failed during noise reduction afterwards. Either way it's a big risk and there's no easy number to stay away from. I have also seen a wonderful 45min startrail shot, noisy as heck but also done on a still working 350D.
> 
> ...



Thanks Garbz.. So the only really safe time is the automatic times on my 350D? Also, I'm not doing star trails. I've been thinking of getting into IR photography.


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## Garbz (Oct 5, 2008)

Oh don't even worry about it. What we're talking about here is 15+ minutes. Infact I'd be comfortable holding the shutter open for 15min on any digital camera. But definitely you can easily go above the 30 second automatic times.

Mind you with IR photography you probably won't need to go beyond 30 seconds anyway. The 350D is several stops more sensitive than the D200 and the most I have held the shutter open for an IR photo is around 10 seconds during a normal mostly bright day.


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## PhilGarber (Oct 5, 2008)

So I could do like a 10min exposure no problem?


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## Garbz (Oct 7, 2008)

Most definitely. The first thing I always assume when these questions pop up are 1hour star-trail exposures. 10min is not a problem, and will probably even look quite good and relatively noise free.


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