Boieng747-400 From , joined Dec 1969, posts, RR: Reply 2, posted (9 years 4 months 5 days 2 hours ago) and read 2808 times:
Have you tried taking your long exposures with a tripod? The red, blue, green dots might simply be the fact that you have moved your camera. If you have used a tripod then it might actually be a problem with the camera.
Like Daniel said easiest way is to post an example...
Boieng747-400 From , joined Dec 1969, posts, RR: Reply 4, posted (9 years 4 months 5 days 2 hours ago) and read 2792 times:
I've never come accross that problem. I'm sure some other people will be able to give you an answer, probably down to either your memory card or your CCD (Image Sensor). I'm sure someone like CKW will be able to nail down your problem.
TWAMD-80 From United States of America, joined Oct 2001, 1006 posts, RR: 4 Reply 5, posted (9 years 4 months 5 days 1 hour ago) and read 2785 times:
Hi! I had the Olympus C-740 and I tried a few shots at the night sky and I got some dots, however it wasn't to the extent as yours. I would get some small light-rust color dots, but I think those were normal and related to the Image sensor.
Two A-4's, left ten o'clock level continue left turn!
YEGPIX From Canada, joined Mar 2002, 159 posts, RR: 3 Reply 10, posted (9 years 4 months 4 days 22 hours ago) and read 2757 times:
Martin, unfortunately your camera does not have any form of noise reduction built in so not alot can be done about the noise I see in these pics. This is the same type of noise I saw in my old C700UZ. The C730, 740, 750UZ have automatic noise reduction built in which would kill the noise. Sorry to bring on the bad news.
JeffM From United States of America, joined May 2005, 3266 posts, RR: 53 Reply 11, posted (9 years 4 months 4 days 21 hours ago) and read 2747 times:
"You try shooting in RAW? Not that it might make a difference but still worth a try.
Maybe you missed the part where he mentioned he used an Olympus C-720?
I took some long exposures at night with my old C-700 and never got that amount of noise. They almost look like 'stuck' pixels.. I suppose you could try using something like Fred's High ISO noise removal actions.
Redfox From United Kingdom, joined Sep 2003, 172 posts, RR: 2 Reply 12, posted (9 years 4 months 4 days 19 hours ago) and read 2730 times:
Agreed with JeffM
The dots do appear to be dead pixels. To confirm this take several shots of the same scene using a tripod but vary the exposure time. If the 'dots' are brighter when the exposure is longer then its definitely dead pixels. Do not worry about it as every CCD will have an amount of dead pixels that are 'stuck' on or off.
Try using the clone stamp tool in photoshop to remove them.
Staffan From , joined Dec 1969, posts, RR: Reply 14, posted (9 years 4 months 4 days 15 hours ago) and read 2685 times:
I think you can take a second exposure with the lens cap on. Then you subtract the second exposure from the first one (since all the hot pixels are the same in both shots). I've heard that astronomy photographers shooting digital does it that way. Do a search on it...