Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-26-2019, 02:12 PM   #1
Senior Member
gerardbaron's Avatar

Join Date: Apr 2011
Location: Mississauga (Canada)
Photos: Albums
Posts: 115
K-1 mkII long exposure in camera processing

Playing with ND filter with a K-1 mII.
I found that an exposure of 30 secondes in bulb mode takes forever to process in camera before the picture reveals.
I figure out that a 30 seconds exposure takes about more than 15 seconds to process in camera.
A 80 seconds takes at least 1 minutes.
Is it a normal behavior?
Should I change any setup in camera?
Thank you for your help.

Read more at: K-1 MK2 Long Exposure Performance - Page 2 - PentaxForums.com

02-26-2019, 02:14 PM   #2
Site Supporter
Site Supporter
enoeske's Avatar

Join Date: Jul 2009
Location: Surprise, Az
Photos: Gallery
Posts: 2,043
QuoteOriginally posted by gerardbaron Quote
Playing with ND filter with a K-1 mII.
I found that an exposure of 30 secondes in bulb mode takes forever to process in camera before the picture reveals.
I figure out that a 30 seconds exposure takes about more than 15 seconds to process in camera.
A 80 seconds takes at least 1 minutes.
Is it a normal behavior?
Should I change any setup in camera?
Thank you for your help.

Read more at: K-1 MK2 Long Exposure Performance - Page 2 - PentaxForums.com
Turn off Dark Frame Subtraction and it will be almost instantaneous (might be called something different, I can't remember)
02-26-2019, 02:22 PM   #3
Loyal Site Supporter
Loyal Site Supporter
pschlute's Avatar

Join Date: Mar 2007
Location: Surrey, UK
Photos: Gallery
Posts: 2,682
QuoteOriginally posted by gerardbaron Quote
Is it a normal behavior?
Yes. Normal behaviour. You can disable it if you want to deal with the noise a long exposure creates yourself.
02-26-2019, 02:35 PM   #4
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 48,154
QuoteOriginally posted by gerardbaron Quote
Playing with ND filter with a K-1 mII.
I found that an exposure of 30 secondes in bulb mode takes forever to process in camera before the picture reveals.
I figure out that a 30 seconds exposure takes about more than 15 seconds to process in camera.
A 80 seconds takes at least 1 minutes.
Is it a normal behavior?
Should I change any setup in camera?
Thank you for your help.

Read more at: K-1 MK2 Long Exposure Performance - Page 2 - PentaxForums.com
The setting to disable is called "slow shutter speed noise reduction". This noise reduction is effective at removing hot pixels that come from sensor hear, but the processing time is roughly equivalent to the duration of the exposure itself.

If image quality is paramount, you can do DFS processing after the fact by snapping a dark frame manually.


Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

02-26-2019, 03:24 PM   #5
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,927
As otgers said. Starting at about 30 seconds the camera takes a dark frame of the same duration to remove artifacts created by the length of tge exposure (heat related sensor pixel noise). As Adam said you can manually create your own dark frame to let Lightroom or another tool manually subtract this noise. The key is similar conditions and durations.
02-26-2019, 04:21 PM   #6
Senior Member
gerardbaron's Avatar

Join Date: Apr 2011
Location: Mississauga (Canada)
Photos: Albums
Posts: 115
Original Poster
QuoteOriginally posted by UncleVanya Quote
As otgers said. Starting at about 30 seconds the camera takes a dark frame of the same duration to remove artifacts created by the length of tge exposure (heat related sensor pixel noise). As Adam said you can manually create your own dark frame to let Lightroom or another tool manually subtract this noise. The key is similar conditions and durations.
How you do that in Lightroom ?
02-26-2019, 04:52 PM   #7
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,927
QuoteOriginally posted by gerardbaron Quote
How you do that in Lightroom ?
My mistake. I meant Photoshop. And I'm not an expert on the method.
02-26-2019, 05:02 PM   #8
Senior Member
gerardbaron's Avatar

Join Date: Apr 2011
Location: Mississauga (Canada)
Photos: Albums
Posts: 115
Original Poster
QuoteOriginally posted by Adam Quote
The setting to disable is called "slow shutter speed noise reduction". This noise reduction is effective at removing hot pixels that come from sensor hear, but the processing time is roughly equivalent to the duration of the exposure itself.

If image quality is paramount, you can do DFS processing after the fact by snapping a dark frame manually.
Hello Adam
How do you snap a black frame in photoshop?
Do you create two layers one with the photo and the other one with
the black one and then use mode substrat ?
Gerard

02-26-2019, 05:06 PM   #9
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 48,154
QuoteOriginally posted by gerardbaron Quote
Hello Adam
How do you snap a black frame in photoshop?
Do you create two layers one with the photo and the other one with
the black one and then use mode substrat ?
Gerard
Basically, you subtract all black from the dark frame, which leaves you with the hotspots. Then, subtract the hotspots from the image that was captured. I'm sure there are tutorials online- not sure what the exact filter would be.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

02-26-2019, 05:37 PM   #10
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,927
Try posing the question in one of the astrophotography threads or forums if you can't find it here.
02-27-2019, 12:26 AM   #11
Pentaxian




Join Date: Jan 2011
Location: New York
Posts: 4,206
QuoteOriginally posted by gerardbaron Quote
Playing with ND filter with a K-1 mII....
You're taking daylight photos with the ND, correct? I think you can just ignore dark frame subtraction for now - you won't notice a tiny bit of noise in scenes that aren't filled with black. Turn off slow shutter speed noise reduction.

Only invest time learning about dark frames if you do astrophotography and night landscapes.
02-27-2019, 01:50 AM   #12
Forum Member




Join Date: Oct 2018
Posts: 92
Is in-camera dark frame subtraction officially documented anywhere?
02-27-2019, 05:49 AM   #13
Pentaxian
MJKoski's Avatar

Join Date: Aug 2016
Posts: 1,281
K-1 II handles very long exposures just fine without DFS in-camera. 20C ambient temp gives 4-5min easily and 5-15mins in subzero temperature. This is more what MK1 is able to handle although it is fine as well. I think KP and MK2 might use the accelerator to filter out long exposures. KP particularly is interesting case as it beats many FF cameras when doing long exposures without DFS.
02-28-2019, 09:12 AM   #14
Site Supporter
Site Supporter




Join Date: Aug 2014
Location: Texas
Posts: 214
Quick pseudo-related question for y'all - does Long Shutter NR affect the RAW file, or just the JPG?
02-28-2019, 03:16 PM   #15
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 14,927
QuoteOriginally posted by disasterfilm Quote
Quick pseudo-related question for y'all - does Long Shutter NR affect the RAW file, or just the JPG?
As far as I understand - both. The subtraction is done before the file is saved. BUT I can't find a citation for this and while I have shot with it on in a number of situations I don't know that I would have noticed it off.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, exposure, exposure in camera, full frame, full-frame, k-1, k-1 mkii, k1, mkii long exposure, pentax k-1, process
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Long exposure looks like multi-exposure Paul the Sunman General Photography 13 01-03-2017 09:43 PM
Long exposure shots, ND filters and multi-exposure averaging rrstuff Photographic Technique 17 10-19-2013 12:50 PM
Long exposure / provia 200 : how to know the good exposure compensation ? aurele Pentax Film SLR Discussion 3 02-18-2012 06:58 PM
How long will fresh batteries last in long exposure? tnis0612 Troubleshooting and Beginner Help 6 05-18-2010 09:11 AM
Night photography with K10D - High ISO short exposure VS Low ISO long exposure pw-pix Pentax DSLR Discussion 10 02-03-2008 01:37 AM



All times are GMT -7. The time now is 10:19 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top