Pixel question? (long drawn out, boring question).....

[builder24car]

I hope I can ask this where it makes sense? I was shooting a church and graveyard last night. When I got the pics on my computer I thought to myself I don't remember any green and red stars in the sky? Then I noticed they were in the exact same spot in every pic. Then it hit me that it was pixels I was seeing. *slaps forehead* Is this just a nighttime thing and something I should be concerned about? Best I remember I was shooting at an ISO of 400. I honestly can't remember the F number and shutter speed. All I know is I was freezing and getting pissed off about what seemed like a non stop stream of cars coming by that I had to wait on. I shoot with an Olympus E-500 and that's why I was wanting to ask the Olympus people.

[jekostas]

Yeah, what's happening is that the sensor is heating up because of the long exposure and causing those "spots" to appear. It's quite normal, it happens to all digital cameras, and the bigger the sensor, the worse the problem (heat increases geometrically compared to size).

What you want to do is when you do long exposures (over 5 seconds or so) is turn on the camera option called "Noise Reduction", should be in the first menu. What it does is take a second exposure right after the first with the shutter closed, and compares the two pictures. Any weird lights present in the second picture are automatically removed from the first. It'll double your exposure times (because you're taking the picture twice), but will also save you the time of cloning out the spots in post-processing.

This is a pretty common technique used in astrophotography, called "dark frame subtraction".

If that doesn't work, try pixel mapping again.

[builder24car]

Thanks jekostas, I appreciate that! I do have my camera set in noise reduction. I've never tried pixel mapping so that's something I'll need to look into I guess. I'll try some other settings as well using a faster shutter speed, etc.

[TheWengler]

I wouldn't worry about it. Use whatever SS you need. I think the default chroma noise reduction setting from Adobe's RAW editor gets rid of those hot pixels anyway.

[raven15]

Thanks jekostas, I appreciate that! I do have my camera set in noise reduction. I've never tried pixel mapping so that's something I'll need to look into I guess. I'll try some other settings as well using a faster shutter speed, etc.

You've never tried pixel mapping? Give it a shot first. I run it on my cameras every few months, or if I see a dead pixel .

I wouldn't worry about it. Use whatever SS you need. I think the default chroma noise reduction setting from Adobe's RAW editor gets rid of those hot pixels anyway.

Adobe's editor would fix it, except builder24car doesn't have any Adobe products .

[builder24car]

I think tomorrow is going to be a rainy day, so I'll look into that pixel mapping stuff Raven. I always get nervous and worry I might mess something up when doing stuff like that.

except builder24car doesn't have any Adobe products

Like Raven said Lukas, I don't have any Adobe products. For that matter I don't have ANY post processing software. That might be a good thing because if I did I'd never get anything done for messing with pics, etc.

[jekostas]

I think tomorrow is going to be a rainy day, so I'll look into that pixel mapping stuff Raven. I always get nervous and worry I might mess something up when doing stuff like that..

I swear, it's really, really easy. Pretty well impossible to screw up. Just open up your menu, go to the last list of options, press Pixel Mapping, and "Start". Let it run until status bar finishes and the menu comes back up, you're done. That's it. Takes like, 15 seconds, maybe.

Edit: Okay, just timed it on my E-510 - 12 seconds.

[raven15]

Yeah, pixel mapping is completely automated and impossible to screw up. No worries there.

I'm almost wondering if my E-410 has a defective sensor, I must have mapped out 50 pixels so far. Only have a little over 10 million left!

[builder24car]

Ya'll were right, the pixel mapping was a piece of cake and I was worried about nothing. Course now if it would ever stop raining so I can get out at night.

[TheWengler]

Adobe's editor would fix it, except builder24car doesn't have any Adobe products .

Oh ok, I'll make a note of it in my book of who has what

Like Raven said Lukas, I don't have any Adobe products. For that matter I don't have ANY post processing software. That might be a good thing because if I did I'd never get anything done for messing with pics, etc.

How do you get by w/ no post processing software? It's a pretty big part of digital photography.