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DPChallenge Forums >> Hardware and Software >> Anyone ever see this problem?
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 07/12/2002 03:01:35 AM · #1
I have an Olympus D490Z that is 1 year and 2 months old (guess how long the warrenty was for)... I just started to notice that for low light shots, I''ve been getting a green dot in the center near the bottom of the photo. Here is an example (I didn''t resize so the flaw would show up in all it''s glory)

Can anyone tell me if I''m now limited to well lit subjects or that I''m needlessly worrying. I cleaned and inspected the lens and see nothing there.

H E L P ! ! !

PS ~ Link isn''t working to tripod... I''m going to set up a pbase account and will edit in a minute. Thanks

Fixed :) pbase is great!

* This message has been edited by the author on 7/12/2002 3:02:16 AM.

* This message has been edited by the author on 7/12/2002 3:08:21 AM.

* This message has been edited by the author on 7/12/2002 3:12:55 AM.

* This message has been edited by the author on 7/12/2002 3:14:28 AM.
 07/12/2002 04:43:14 AM · #2
You have a stuck pixel on your CCD (shows the same value in every exposure). It shows up in your low light shots due to the contrast between that pixel and the bg, but it's always there regardless of the lighting. Not a big deal; it happens to most CCDs sooner or later. I've got three or four. The newer Oly cameras have a 'pixel mapping' feature that will identify the stuck pixel, disable it, and use interpolated data from the surrounding pixels to determine its value. I don't know about your camera, but you might check if this feature is in the manual. For applications outside of dpchallenge you can clone the offending green booger out yourself, and reducing your image to web size should minimalize it for posts here. I think most of us wouldn't downgrade an image for a stuck pixel, so don't sweat it.
 07/12/2002 09:48:59 AM · #3
Maybe you could wait for a UFO challenge, then enter it ;-)
 07/12/2002 10:20:47 AM · #4
Mike, don’t worry I see the same green star from my backyard on certain late nights afterâ€Â¦ ;-)
 07/12/2002 01:30:55 PM · #5
It is annoying but I wouldn't worry about it to much. I have the same problem and actually have one of those green dots in my current entry.

Actually, judging by my current score...maybe it does matter! :~}
 07/12/2002 02:16:43 PM · #6
Thanks all... I guess brightly lit shots will be the norm for me for a while :)

I noticed that someone suggested a One Color challenge along the lines of the RED challenge from a while back. Do you suppose we could do GREEN? :)
 07/12/2002 02:52:47 PM · #7
You could use the Despeckle command in PhotoShop (or something similiar) with a radius of 1 pixel...

Not only is it DPChallenge legal, it will almost always do a good job of removing stuck and/or hot pixels from your image.

For best results, though, use the lowest compression setting your camera will allow to prevent the stuck pixel's value from being spread across several pixels.
 07/12/2002 03:30:26 PM · #8
Originally posted by sohr:
You could use the Despeckle command in PhotoShop (or something similiar) with a radius of 1 pixel...

Not only is it DPChallenge legal, it will almost always do a good job of removing stuck and/or hot pixels from your image.

For best results, though, use the lowest compression setting your camera will allow to prevent the stuck pixel's value from being spread across several pixels.

Thanks! I normally use SHQ (Super High Quality) JPG setting. Would it be better to move to TIF? I kind of hope not because it will take me from 45 or so shots (64meg card) down to around 11 shots (ouch)

Again, Thanks all!
 07/12/2002 04:01:53 PM · #9
I think TIFF mode would be slightly better... but probably way overkill for the problem. I think your current compression level will be just fine.

Here is a small section of your last submitted work (with the green dot):



Just sharpen this a little, and you could almost never tell a green pixel was there!

* This message has been edited by the author on 7/12/2002 4:07:46 PM.
 07/12/2002 04:51:56 PM · #10
I also wanted to add that for NON-DPCHALLENGE photos, and for photos with numerous "hot" or "cold" pixels:

You can get even better results by taking a single photo, with your lens cap on (!), using the same shutter speed as the photo you want to improve.

Then add the (hopefully) mostly black photo as a new layer using PhotoShop. Use the ''difference'' blending mode for this layer, and adjust the opacity until you like what you see.

Works like a charm!



* This message has been edited by the author on 7/12/2002 4:54:04 PM.
 07/22/2002 01:03:23 PM · #11
I just recently purchased my Olym C4040z I had the same problem - that darn green pixel - I had to clone it out of every picture (prior to DPC). Then I visited the Digital Camera review website and their Forum for Olympus. Suggested the pixel mapping. Although the green pixel still shows on the display (sometimes) I have not seen it in the pictures - thank heavens, then I wouldn't be submitting photos here.

So I guess this is along the same lines as irae.

Good luck.
Ruthann
 07/30/2002 09:48:24 PM · #12
Often stuck pixels camera's will be fix/replaced outside of warrenty, because they are usually caused by faulty manufacturing of the CDD chip.. I may be wrong, It's just what I heard....

Worth talking to the shop you brought it from anyway...
 07/31/2002 12:19:16 AM · #13
And a good thing it hasn't...

If it showed up, you'd have to change your userid to GreenRuthann

sjgleah

Originally posted by RedRuthann:
I just recently purchased my Olym C4040z I had the same problem - that darn green pixel - I had to clone it out of every picture (prior to DPC). Then I visited the Digital Camera review website and their Forum for Olympus. Suggested the pixel mapping. Although the green pixel still shows on the display (sometimes) I have not seen it in the pictures - thank heavens, then I wouldn't be submitting photos here.

So I guess this is along the same lines as irae.

Good luck.
Ruthann


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