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02-22-2013, 05:17 PM   #1
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Blue and Red "Electronic-looking" Orbs

Hello everyone!

Last night I took some night shots of a Japanese temple. I didn't use my flash but used a 1600 ISO and 30" exposure. When I pulled my photos up on my monitor, I noticed that some of my pictures had blue and red orbs like looked like LED lights and there were in the same exact place on the screen in photos shot at different angles. Can anyone tell me what's going on?

02-22-2013, 05:19 PM   #2
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Can you upload a shot for us to review?
02-22-2013, 05:23 PM   #3
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If you had a filter attached to the lens, I'd put betting odds on that being a reflection off of that. Photos would help though.
02-22-2013, 05:50 PM   #4
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I hope this works. Here are four photos that I took. These are not all of them, but I included photos that had the LED light-looking orbs and photos that do not. I didn't not have a lens filter. I used MY K-5 w/kit lens, ISO 1600 and 30" exposure.



02-22-2013, 05:57 PM   #5
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I couldn't see the "LED Dots" in those four photos, here are two more I know for a fact I saw them because I previewed them in iPhoto.
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02-22-2013, 06:01 PM   #6
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Bad pixels which show up in long exposures. Some cameras allow you to "map out" the bad pixels, and/or make a second "dark frame" exposure to detect them.
Note: I don't see anything on the images...
02-22-2013, 06:02 PM   #7
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It's still difficult to see. I zoomed in on the dots and took a screen shot of one of the photos to help.
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02-22-2013, 06:25 PM   #8
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The pink dot is a stuck pixel. Your camera menu has a routine to map it out so that future photos will not use that pixel

02-22-2013, 07:41 PM   #9
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QuoteOriginally posted by monochrome Quote
The pink dot is a stuck pixel. Your camera menu has a routine to map it out so that future photos will not use that pixel
On long exposures a lot more pixels will stick than normal exposures, just due to sensor heat, mapping doesn't help in that situation.
02-22-2013, 08:08 PM   #10
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QuoteOriginally posted by elliott Quote
mapping doesn't help in that situation
Dark frame subtraction should, but that'll add double the time of exposure to the total time of the shot. 30 second exposure would take a full minute, due to 30 second dark frame the camera takes to map the hot pixels.

---edit---
I assume shocktroop5811's k-5 has dark frame subtraction, I know my k200d does.
02-22-2013, 08:12 PM - 1 Like   #11
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QuoteOriginally posted by pezmaker Quote
Dark frame subtraction should, but that'll add double the time of exposure to the total time of the shot. 30 second exposure would take a full minute, due to 30 second dark frame the camera takes to map the hot pixels.

---edit---
I assume shocktroop5811's camera has dark frame subtraction, I know my k200d does.
You beat me while I was scrolling up to re-read how long his exposure was and see whether he mentioned which camera.
02-22-2013, 08:31 PM   #12
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You have hot pixels. Sensors heat up as they are used for longer periods of time. You'll see these little spots pop up somewhat randomly when you make a series of long exposures.

I had the same problem when doing 30 second exposures at iso 800 at night with my K-x. When I edited them in lightroom 3, they were automatically removed. I literally did nothing but load the photos in lightroom and the program removed them. I don't know who else has had this experience with this software.
02-22-2013, 09:08 PM   #13
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Definitely hot pixels, as others have mentioned. Very common to have some in your sensor. Unless you have dozens of them, I believe the conventional wisdom is to map them, but if you did have dozens upon dozens (which is not the case here), then it might be worth a warranty claim.

I had some hot pixels that showed up in exposures around 1 or 2 seconds, and mapping them out cured the problem.

Good luck!
02-22-2013, 09:26 PM - 1 Like   #14
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QuoteOriginally posted by Gerbermiester Quote
You have hot pixels. Sensors heat up as they are used for longer periods of time. You'll see these little spots pop up somewhat randomly when you make a series of long exposures.

I had the same problem when doing 30 second exposures at iso 800 at night with my K-x. When I edited them in lightroom 3, they were automatically removed. I literally did nothing but load the photos in lightroom and the program removed them. I don't know who else has had this experience with this software.
Adobe Camera RAW (which Lightroom uses) does this automatically, even in the Elements version. For a long time I assumed my camera had no hot pixels - I just wasn't seeing them.
02-23-2013, 05:17 AM   #15
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Lightroom does handle this nicely. My Leica M9 developed a hot pixel (red) that shows up on the LCD preview when zoomed in, but I always shoot RAW and convert in Lightroom, so it is never in the resulting files. Good thing, as the M9 does not map out hot pixels - you have to send the camera back to Germany.
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