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Dead Pixel?

PostPosted: Tue Jun 28, 2005 12:43 pm
by Hlop
Hi All!

I found red dot on some of my recent photos it looks like a dead pixel but when I took a shot of white wall it wasn't there.

Here is 100% crop:
Image

So, question is could they appear and the disappear under certain circumstances as, for example, high humidity in Singapore? Or it need particular colour combination to appear? What if I'll bring it to Maxwell and they'll tel me there is no problem but I see the problem is there?

PostPosted: Tue Jun 28, 2005 12:56 pm
by Glen
Mikhail, I have no idea but it looks bigger than one pixel in size. I had an incident when first using eclipse when I put too much on which resulted in a similar output, I cant remember the colour. It went with another clean. Maybe yours is moisture or humidity which was only evident in Singapore?

PostPosted: Tue Jun 28, 2005 1:05 pm
by sirhc55
Mikhail - looks more like a laser sight red spot :roll: :wink:

PostPosted: Tue Jun 28, 2005 1:28 pm
by Hlop
Chris,

That was the very first thing I told to Lara :) At first pic it was on her blouse, and second was on her troat. And as she's working in financial services I asked: "How much have you stolen so they have sent a killer after you?" :)

Back to the topic, so, could it be just a tiny drop of water which came from high humidity and worked as a tiny lens on sensor?

PostPosted: Tue Jun 28, 2005 2:29 pm
by ipv6ready
http://www.starzen.com/imaging/deadpixeltest.htm

This is free tool.

I compared the results between this and a CCD dead pixel remapping software on my D100 and it was very similar. Both picked up almost the same number of dead pixels (off by one) from 7 and slightly different hot pixel result. Not by much though.

Though i think in regards to the hot pixels the "remapper" does not tell me how long the exposure it was taking, so i guessed at three seconds by ear.
On three seconds it was just 6 pixels off. on 30 seconds it was 79 off.

PostPosted: Tue Jun 28, 2005 2:36 pm
by kipper
Sounds feasible, when somebody said it was bigger than 1px I immediately thought it might be light refracting through something.

PostPosted: Tue Jun 28, 2005 2:55 pm
by birddog114
This ones was happening before on this board not so long ago with our member christiand, I could remember clearly what it was but finally, he sent it back to Maxwell to repair with his in-built flash problems.

PostPosted: Tue Jun 28, 2005 3:14 pm
by kipper
Birddog, wasn't that though a thin red line (wasn't that a movie? :)) though that went across the image to like the centre?

PostPosted: Tue Jun 28, 2005 3:26 pm
by Hlop
kipper wrote:Sounds feasible, when somebody said it was bigger than 1px I immediately thought it might be light refracting through something.


If this happened to one shot it might be light refracting or something but it has happened to number of shots.

My only hope - I don't see it anymore - I took few pictures of different objects of different colours and it seems to be fine

PostPosted: Tue Jun 28, 2005 3:29 pm
by birddog114
kipper wrote:Birddog, wasn't that though a thin red line (wasn't that a movie? :)) though that went across the image to like the centre?


On the problems from CD, it was a thin red line same as the laser beam, and it happened to him in any shot which he took.

PostPosted: Tue Jun 28, 2005 3:35 pm
by Hlop
ipv6ready,

Thanks a lot. Interesting tool. I'm just wondering how reliable it is ...

Anyway, I tested few similar shots with this red dot and it didn't show me any of dead pixels. So, let me believe it was a drop of condenced water on CCD (keeping my fingers crossed)