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11-13-2010, 10:13 AM   #1
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Can long exposure times harm the sensor in the K-5?

[mods, please move to general DSLR or other if more appropriate]

The K-5 has proven to be able to take hour+ long exposures w/negligible noise. My question however is, can doing so actually damage the sensor, increasing the noise it produces over time much faster than the normal degeneration of the sensor, if not causing it to fail much sooner than otherwise?

I ask because most if not all the CMOS sensors I've read about used in special-purpose astrophotography setups (which aren't that many) are usually water cooled. And I'm not entirely sure if that is/was done to a) keep it cool and reduce the level of spurious noise produced, or b) to keep it from self-destructing ... I'd always thought, both, but maybe I'm wrong.

Anyone with some [preferably 1st-hand] knowledge in this realm know? I would be more likely to take 120 30s exposures in RAW and stack them than a single 1 hour exposure if there is risk to the sensor w/the latter if stock and not liquid cooled.

11-13-2010, 10:46 AM   #2
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Short answer, No. Don't worry the heat build up would just add more electronic noise, this is why astro cameras use Peltier coolers to bring the aforementioned noise (shot noise) down. Typically to kill silicon junction devices you need temperatures around 150 C!!!! Not going to happen by using your camera unless it's inside an oven.
11-13-2010, 10:46 AM   #3
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I use my old K100D for long Bulb Mode exposures, mainly because I can turn off DFS completely, unlike the K-7.
But it being an relatively elderly, backup body is a factor , so its obvious I have a concern like yours - I don't use my latest camera

My K100D does have an increasing number of hot pixels, not sure if its directly related to long exposures, but the camera and sensor are still going strong. It may die on me tomorrow , who knows ? , but its still working fine right now.

The new K-5 looks like an awesome tool for long exposures, but I do have a bit of concern using my latest and best camera for this strenous (?) task.
11-13-2010, 05:53 PM   #4
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78 Minutes.

Taken the following day...



Same lens, same camera, same card so, I guess no damage..



11-13-2010, 06:30 PM   #5
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QuoteOriginally posted by JeffJS Quote
Same lens, same camera, same card so, I guess no damage..
Well, I never thought there would be instant damage; was wondering if over time the sensor would degrade and/or possibly fail sooner. But regardless, looks like no in any case.
11-13-2010, 07:07 PM   #6
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QuoteOriginally posted by m8o Quote
Well, I never thought there would be instant damage; was wondering if over time the sensor would degrade and/or possibly fail sooner. But regardless, looks like no in any case.
Well, since the oldest K5 in use is probably no more than a month old, Who would Know?

11-13-2010, 07:26 PM   #7
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QuoteOriginally posted by JeffJS Quote
Well, since the oldest K5 in use is probably no more than a month old, Who would Know?
Meant it as a "is the CMOS, used in the K-5, susceptible" query. But yes, certainly, who's to know if its particular CMOS [a different acronym actually] would be equally susceptible if any are... which anyway, seems not.

Last edited by m8o; 11-13-2010 at 07:35 PM.
11-13-2010, 08:01 PM   #8
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QuoteOriginally posted by m8o Quote
Meant it as a "is the CMOS, used in the K-5, susceptible" query. But yes, certainly, who's to know if its particular CMOS [a different acronym actually] would be equally susceptible if any are... which anyway, seems not.
I guess I'm feeling a little snarky tonight.. Sorry for the short sounding response... Fact is, I don't know if it's susceptible. Pentax has put heat protection into the circuits so that if the sensor overheats during Live View, the shutter will close (same with video clips). One would like to think the sensor can take quite a bit in terms of long exposures. Then again, one would like to think a lot of things. Most of which may not be true



11-13-2010, 08:05 PM   #9
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I know my GX10 has developed quite bad sensor blooms from doing long exposures, and every time I do one it gets a little worse. It's to the point that even if I do a bunch of shots in a row at ISO 1600 it can shot up a little. But that is a CCD not a CMOS so there may be a difference.
11-13-2010, 09:30 PM   #10
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This is exactly why I will be buying an extended warranty, most likely from squaretrade.com unless someone knows a cheaper one that is good.
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