Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-04-2010, 10:16 PM   #1
Senior Member




Join Date: Apr 2010
Location: New Mexico
Posts: 179
K7 30 sec exposure problems

I have a k7 and set it up with takumar lenses. I was out shooting a 30 sec exposure of the street at night with an iso level of 100. My picture had some dots on it like static with green, red, orange, blue colors. However once I use a faster shutter they are gone. So i ran some tests with the lens cap on to make sure I don't have dead pixels. The same results. At 1/50 shutter nothing showed up. At 30 sec there is a lot of noise. I have two k7 cameras and both are the same. Anyone else have this problem? Is there a setting I have that makes it this way. Thanks

11-04-2010, 10:36 PM   #2
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,135
Run pixel mapping.
You could turn on noise reduction as well.
11-05-2010, 02:15 AM   #3
Pentaxian
fs999's Avatar

Join Date: Jul 2008
Location: Luxembourg
Photos: Gallery
Posts: 3,715
I had the same problem. Must try this night with my K-5...

Pixel mapping will not help, because it is only at 30 sec exposure...
11-05-2010, 02:33 AM   #4
Veteran Member




Join Date: Dec 2007
Posts: 923
Long exposure with the K-7 at ISO100 is usually pretty clean.
Try setting Long Exposure Noise reduction on at 30secs - that seems to be the limit of what the sensor can handle without NR

11-05-2010, 04:11 AM   #5
Senior Member




Join Date: Sep 2009
Photos: Albums
Posts: 158
Do the pixel mapping anyway, it'll help at least some; works for me. And as suggested, you could also turn on dark frame subtraction, that'll work for sure at the cost of the 2X exposure time, 1X for exposure and 1X for the dark frame.

i do a lot of long exposures, these 2 things keep the hot pixels out. Of course, the K-7 sensor also has a lot of noise in the dark areas of the image on long exposures. Because of that i tend to try to keep my long exposures as short as possible.

Edit:

And long exposures with the K-7 should always be at base ISO. i've run tests and image noise is prominent should i up the ISO.
11-05-2010, 02:37 PM   #6
Forum Member
fewayne's Avatar

Join Date: Oct 2010
Location: Wisconsin
Photos: Gallery | Albums
Posts: 84
"Turn on the dark frame subtraction"? Is there a way to turn it off? If so, I sure didn't know about it!
11-05-2010, 03:32 PM   #7
Pentaxian
kh1234567890's Avatar

Join Date: Sep 2010
Location: Manchester, UK
Photos: Gallery
Posts: 2,405
QuoteOriginally posted by fewayne Quote
"Turn on the dark frame subtraction"? Is there a way to turn it off? If so, I sure didn't know about it!
Custom Item 18 : Slow Shutter Speed NR
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, k7, photography, sec, shutter
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
problems using automatic exposure kx trishytee Pentax DSLR Discussion 8 06-10-2010 10:56 PM
Exposure problems mattmiles Troubleshooting and Beginner Help 11 01-27-2010 10:15 PM
Long exposure problems wombatwal Pentax DSLR Discussion 22 07-24-2008 07:26 AM
why 30 sec exposure philmorley Pentax DSLR Discussion 18 05-12-2008 04:06 PM
Need help with exposure problems and snow photography problems, urgent please respond montezuma Photographic Technique 7 02-24-2008 05:43 PM



All times are GMT -7. The time now is 02:35 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