Logitech Webcam Mod query

[BlueAstra]

I thought I would have a go at webcam photos to see if I like it. Start cheap I thought before spending loadsamoney, so I got a Logitech E5400 and pulled it apart to take the lens out. I then glued an old photo canister on as an eyepiece guide and off we go!

Still waiting for the cloulds to go and night to come, I put it on the telescope and focussed on a far away pylon to get the hang of it. On taking a 'flat' field and 'dark' field I got some rather odd results (see attachments).

The dark field (telescope aperture covered) was a non uniform pink, and the flat field (telescope pointed a plain wall) was the same with a white patch in the centre. I know the 'object' was out of focus, but can anyone explain what I'm seeing, and is it normal?

[beamish]

White balance adjustment ?

[barkis]

You haven't left any LED'S unmasked that could be throwing light onto the sensor.? Just a thought.

Ron.

[beamish]

Ah, good point Ron, there 's usually some kind of indicator light on these things .

[BlueAstra]

I don't think so. I've tried adjusting white balance and it doesn't affect it. Colour contols will make it more or less intense, but nothing seems to change the non-uniformity.

[BlueAstra]

You haven't left any LED'S unmasked that could be throwing light onto the sensor.? Just a thought.

Ron.

Not sure. Its only a simple webcam, and I re-assembled the case after removing the lens. Didn't switch it on while I could see the pcb. Could take it apart to have another look. No LEDs visible from the outside.

[barkis]

I mentioned LED's, because I modified my Logitech Fusion webcam last year, and it had two led's on the PCB. I had to mask them off.

I took the internals out of the Logitech case though, and put it into a small ABS box from Maplin. I bolted a 2" nosepiece to the box where the lens housing was.

If you left your pcb inside it's original case, I doubt if any stray light will impinge on the sensor.

Ron.

[BlueAstra]

Just had a chance to take it outside, and yes there is a nasty green glow from an LED. Didn't notice it during the day when I was playing with it. Will take it apart tonight to mask it. Still not quite sure why a green LED gives a purple image.