super long exposure.

patrickhh · 04-09-2008, 07:47 AM

Originally posted by vizjerei

Hmm I don't have K20D... so what do you mean but Darkframe can't be turned off? is it its NR auto on even you told it not to?

I don't have K20D either ... but this is what other K20D owners are reporting.

https://www.pentaxforums.com/forums/pentax-dslr-discussion/22521-finally-some...bout-k20d.html

I will probably delay my K20D "upgrade", until this bug is sorted out.

smc_pentax_fan · 06-23-2010, 10:28 AM

might be out of date but k10 will do 1 hour exposures with a bit of ccd heat (in the upper part of the picture).
k20d has dark frame substraction(it will repeat the exposure with the courtain closed)
can somebody please post samples done with the k20d and share the experience ?! thanks!

**Ash** · 06-23-2010, 12:16 PM

Welcome to the forum smc pentax fan.
Since I last posted in this thread, I've had some experience shooting long exposures with the K20D. Not so impressive as the earlier CCD-sensor dSLRs, as you can see in my thread addressing this very issue:
https://www.pentaxforums.com/forums/post-your-photos/74773-night-country-trai...iso-noise.html

I've had no problems getting clean 1hr exposures with the K10D at ISO 160-250, but the K20D has been a challenge getting a clean 5-15min exposure even at ISO 100. C'est la vie.

The K-x does a much better job from what I hear.

mysticcowboy · 06-24-2010, 01:41 PM

Originally posted by Ash

Anyone tried longer exposures for star trails with the K20D yet?
I'm curious to know if the K20D's 'cooler' sensor permits longer exposures without the hot pixels.

I don't do star trail photography, but do take a lot of night building shots.

The K20D has a built in fix for long exposure hot pixels. The good news is that it works well. I get a bit of noise but nothing objectionable up to 15 minutes at ISO 200. The bad news is that it takes a second exposure of the same length. So a 15 minute exposure will take more than 30 minutes to complete. There's a bit of extra time on top of the second exposure for processing. This feature in not optional. You can't turn it off and process for hot pixels manually.

BTW, 30 minutes of continual processing runs the battery down quickly. Make sure you're charged up.

Last edited by mysticcowboy; 06-24-2010 at 01:51 PM.

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04-09-2008, 07:47 AM	#16
patrickhh Forum Member Join Date: Apr 2008 Location: Hamburg Posts: 70	Originally posted by vizjerei Hmm I don't have K20D... so what do you mean but Darkframe can't be turned off? is it its NR auto on even you told it not to? I don't have K20D either ... but this is what other K20D owners are reporting. https://www.pentaxforums.com/forums/pentax-dslr-discussion/22521-finally-some...bout-k20d.html I will probably delay my K20D "upgrade", until this bug is sorted out.

06-23-2010, 10:28 AM	#17
smc_pentax_fan Inactive Account Join Date: Aug 2008 Location: Romania, Bucharest Posts: 1	might be out of date but k10 will do 1 hour exposures with a bit of ccd heat (in the upper part of the picture). k20d has dark frame substraction(it will repeat the exposure with the courtain closed) can somebody please post samples done with the k20d and share the experience ?! thanks!

06-23-2010, 12:16 PM	#18
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Welcome to the forum smc pentax fan. Since I last posted in this thread, I've had some experience shooting long exposures with the K20D. Not so impressive as the earlier CCD-sensor dSLRs, as you can see in my thread addressing this very issue: https://www.pentaxforums.com/forums/post-your-photos/74773-night-country-trai...iso-noise.html I've had no problems getting clean 1hr exposures with the K10D at ISO 160-250, but the K20D has been a challenge getting a clean 5-15min exposure even at ISO 100. C'est la vie. The K-x does a much better job from what I hear.

06-24-2010, 01:41 PM	#19
mysticcowboy Veteran Member Join Date: Apr 2009 Location: port townsend, wa Photos: Albums Posts: 968	Originally posted by Ash Anyone tried longer exposures for star trails with the K20D yet? I'm curious to know if the K20D's 'cooler' sensor permits longer exposures without the hot pixels. I don't do star trail photography, but do take a lot of night building shots. The K20D has a built in fix for long exposure hot pixels. The good news is that it works well. I get a bit of noise but nothing objectionable up to 15 minutes at ISO 200. The bad news is that it takes a second exposure of the same length. So a 15 minute exposure will take more than 30 minutes to complete. There's a bit of extra time on top of the second exposure for processing. This feature in not optional. You can't turn it off and process for hot pixels manually. BTW, 30 minutes of continual processing runs the battery down quickly. Make sure you're charged up. Last edited by mysticcowboy; 06-24-2010 at 01:51 PM.