Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-06-2007, 07:34 PM   #1
Inactive Account




Join Date: Jan 2007
Posts: 6
Render Delay

Since I'm interested in using my Pentax camera (if I'm lucky enough to get one) for long-exposure and nighttime photography, about how long does it take to render a Bulb or 1-second+ image on a Pentax K100/110D? With my Canon, it takes about as long to render the image (noise-reduction) as it does to take the photo. Therefore, a 15-second photo ends up taking 30 seconds to complete. Also, does turning the noise-reduction for long exposures off change the render time at all? Thanks!

01-06-2007, 09:54 PM   #2
New Member
SelrahCharleS's Avatar

Join Date: Dec 2006
Location: Wisconsin, USA
Posts: 20
You can turn it off...

Its called dark frame subtraction. It takes a blank photo with the same amount of time as your original exposure and uses that to map out the hot pixels you get. It can be turned off easily by going into the menu. I leave it off for shooting fast action like lightning(fast action long exposures, interesting thought)... but if you want the highest quality, leave it on. If you want quick shot to shot times though, you can turn it off as long as you don't mind hot pixels. Once turned off there will be no delay between shots unless you fill up your buffer(which would happen if you were clicking away rapidly, either on long exposures or at 1/1000).

Here is one of my photos that was shot with long exposure NR off. It has a few noticeable hot pixels, but for what I was doing I consider it acceptable(they are easily cloned away too if you really like the photo and are willing to put some time into it).


Pentax *ist DS... something like a 10 or 15 second exposure.

Last edited by SelrahCharleS; 01-06-2007 at 09:57 PM. Reason: added additional information
01-06-2007, 10:40 PM   #3
Inactive Account




Join Date: Jan 2007
Posts: 6
Original Poster
Ah, I think I've heard of the dark frame subtraction before. I'm glad that cutting that off eliminates the delay. That will come in handy for things like lightning photography, but I'd probably be better off leaving it enabled for night sky photos since hot pixels and stars might be hard to discern. And yes, I've seen worse hot pixel problems than that, which is pretty reassuring. Thanks for the help!

Very interesting lightning photo by the way.
01-07-2007, 05:59 AM   #4
Veteran Member
foxglove's Avatar

Join Date: Sep 2006
Location: Atlantic Canada
Photos: Gallery
Posts: 1,049
QuoteOriginally posted by tparker Quote
I'd probably be better off leaving it enabled for night sky photos since hot pixels and stars might be hard to discern.
You can get away without it, apparently, although I've not figured this out myself, not having much use for it. You can leave noise reduction off, and do your own dark frame, then use that to remove the hot pixels. I'm sure someone else can explain how to do it - in fact, I'd be interested to know myself!

Come to think of it, doesn't ACR automatically map out hot pixels? And if it does, how does it tell the difference between a hot pixel and a star? Anybody have thoughts on this?

Julie

01-07-2007, 10:26 AM   #5
New Member
SelrahCharleS's Avatar

Join Date: Dec 2006
Location: Wisconsin, USA
Posts: 20
QuoteOriginally posted by foxglove Quote
You can get away without it, apparently, although I've not figured this out myself, not having much use for it. You can leave noise reduction off, and do your own dark frame, then use that to remove the hot pixels. I'm sure someone else can explain how to do it - in fact, I'd be interested to know myself!

Come to think of it, doesn't ACR automatically map out hot pixels? And if it does, how does it tell the difference between a hot pixel and a star? Anybody have thoughts on this?

Julie
I've never done it that way, although I have considered it... here is a link that tells how to do it, though I'm not sure it is the best tutorial. Astromart Articles - How to Subtract Dark Frames with Photoshop, Photoshop LE, or Photoshop Elements
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, image, pentax, photo, photography, render
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Preview delay NikonToPentax Pentax K-5 13 09-19-2011 10:19 AM
Tom DeLay..... Guilty jeffkrol General Talk 8 11-29-2010 10:47 AM
K-7Instant review delay barkii Troubleshooting and Beginner Help 2 10-16-2010 07:15 AM
delay to preview braver Pentax DSLR Discussion 8 02-25-2010 03:20 PM
Why can't the K7 render these details? sammie Pentax DSLR Discussion 18 12-18-2009 04:35 PM



All times are GMT -7. The time now is 03:29 PM. | 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