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Old Jun 15, 2009, 4:04 PM   #1
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Default Red Dots that are appearing in Photos

Can anyone tell me what these red dots are from that are in these two photos? They don't appear all the time, but sometimes there are 3 dots or other times 15 or so dots.
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Old Jun 15, 2009, 6:03 PM   #2
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I'm not sure about the first shot but the 2nd shot appears to be due to reflections inside the lens. Did you have a lens hood on?

If in the first shot they are about the size of a pixel then this is likely to be hot pixels which can happen at higher ISO and longer shutter speeds. If you can show a 100% crop of the affected area that will help.
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Old Jun 15, 2009, 6:38 PM   #3
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I notice that both the red eliptical spots are somewhat consistent in shape and distance apart in each photo. While more evident in the second they are also visible in the left hand side half inch in from the left near the wood molding. It seems that they are rotated to different positions in each case but there is definately something going on there. Perhaps, as Mark says, its just light reflecting but Ive never seen it happen like that before. Keep us posted if you find out exactly what it is.
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Old Jun 15, 2009, 8:21 PM   #4
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I did crop them, but I hope I did it right. The first pic was at 1/10 sec, F4 and ISO 1600. The second pic was 1/25 sec F4 at ISO 400. I did not have a lens hood on. If it is hot pixels, how can I prevent them? Does that mean there is something wrong with my camera?
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Old Jun 15, 2009, 8:31 PM   #5
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Are you sure it's in the camera? I've seen similar patterns from light catching those crystal ornament thingies which folk hang in the window as mobile decorations… …or perhaps a piece of jewelry, say an ear-ring catching the light. The spots on the door in the first picture look like a blur…

The test for hot-pixels is to put the lens cap on, set the camera to manual, and take some frames, then examine them really closely at maximum magnification. You might see more at high ISO settings.

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Old Jun 15, 2009, 9:50 PM   #6
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There may have been something shiny in the room with the dots above the door but I can't say for sure.

I tried the test for hot pixels at different ISO settings and some came up when I set the ISO to 1600. There were red, blue, green and white pixels. Not a whole lot, but they were there. Is this something that will pose a problem? Is there a solution?

Thank you all for your input.
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Old Jun 15, 2009, 9:51 PM   #7
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Quote:
Originally Posted by CameraShy75 View Post
I did crop them, but I hope I did it right. The first pic was at 1/10 sec, F4 and ISO 1600. The second pic was 1/25 sec F4 at ISO 400. I did not have a lens hood on. If it is hot pixels, how can I prevent them? Does that mean there is something wrong with my camera?
Did you shoot these in jpeg or RAW? It looks like the red specks in the first picture are probably hot pixels which haven't been cleaned up by noise reduction. If the pics were taken RAW, you can reprocess and probably eliminate them. If jpeg, you need to do a bit of post-processing. The touch-up tool in Photoshop (Elements, too) will take care of them. Dark areas in high ISO shots especially tend to have these and there is nothing wrong with your camera.

The bright spots shown in the second picture look like reflected light from something external. Can you be sure they were not there when you took the shot? If yes, then they may be caused as Mark mentioned by internal reflections in the lens. This can happen if there is a bright light source (a chandelier, maybe?) just outside the field of view of the lens. Light strikes the front lens element at an angle and some of it reflects back into the lens. The softness and shape are clues as well. Were you using a stabilized lens? If so, this could account for the oblong shape.
A lens hood will help prevent that sort of thing.
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Old Jun 16, 2009, 1:44 AM   #8
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I didnt even notice the spots on the jacket. I was referring to the large oblong spots on the wall. Not so noticeable because the colors are close. These are too large to be pixel problems.
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Old Jun 16, 2009, 9:33 AM   #9
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I shot these photos in jpeg and I did not use a stabalized lens. I have actually only used this camera only a handful of times (and absolutely love it!). It was a refurbished camera and I want to make sure there is nothing wrong with it before the warranty is up (but I think it is already). I am going to ask my cousin if there was a suncatcher in the window or something because there are other pics with these dots in like the ones above the door, but I didn't post because I didn't think they would appreciate me posting their faces.

Quote:
Originally Posted by VTphotog View Post
Did you shoot these in jpeg or RAW? It looks like the red specks in the first picture are probably hot pixels which haven't been cleaned up by noise reduction. If the pics were taken RAW, you can reprocess and probably eliminate them. If jpeg, you need to do a bit of post-processing. The touch-up tool in Photoshop (Elements, too) will take care of them. Dark areas in high ISO shots especially tend to have these and there is nothing wrong with your camera.

The bright spots shown in the second picture look like reflected light from something external. Can you be sure they were not there when you took the shot? If yes, then they may be caused as Mark mentioned by internal reflections in the lens. This can happen if there is a bright light source (a chandelier, maybe?) just outside the field of view of the lens. Light strikes the front lens element at an angle and some of it reflects back into the lens. The softness and shape are clues as well. Were you using a stabilized lens? If so, this could account for the oblong shape.
A lens hood will help prevent that sort of thing.
brian
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Old Jun 16, 2009, 9:35 AM   #10
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That's ok, I didn't notice those spots you have circled. I actually think those spots are from the lights from the dj.

Quote:
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I didnt even notice the spots on the jacket. I was referring to the large oblong spots on the wall. Not so noticeable because the colors are close. These are too large to be pixel problems.
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