Pi-Camera pink tinted center

I have "daylight" Pi camera as a webcam at capturing images every 30
seconds at 960 x 540 using python script and the picamera python
module.
There is subtle red tinted area in the central area of the image.
Normally visible on clouds:
formatting link

It's not the LED as I've turned that off and at night with it on the
reflection is quite obvious on the left hand side.

Is a subtle central red tint a known problem with PiCameras?
Is it a function of only capturing a 960x540 image rather than full
Pi Camera resolution? I can resize later when I add the text.
--
Cheers 
Dave.
Reply to
Dave Liquorice
Loading thread data ...
Looking around the net with Google purple/red/pink tints to such cameras ar e common. You'll see a number of posts about HTC phones, Android devices an d such with the same basic camera and tint problems. You could recolor thin gs with software but your problem seems to be only in part of the image, wh ich will make that more difficult. If the whole picture was tinted that's m uch easier to correct, but it still could be done. It would just take very specialized software setup for that one camera ;(
Reply to
bcw142
Thanks for that, not surprised it is after all a cheap comodity camera module.
The patch is more or less consistent in area but it doesn't always appear to be there. On the 30 sec frame interval time lapse movies it's sometimes obvious other times not. Maybe it's an exposure function, I'm currently using "matrix".
--
Cheers 
Dave.
Reply to
Dave Liquorice
Might it be internal reflection? I'd try fitting a hood to the lens.
Reply to
Rob Morley
It looks far too diffuse. I'm caputuring 960 x 540 and the affected patch is more or less full height, circular and centred.
It's not a refracted highlight, not well enough defined and it's visible when there is no point source (aka the sun) shining into the lens. It doesn't move either. It could be a more general lens flare but they tend to just lift the whole image uniformally and without a colour tint.
The module is tapped to the glass of a double glazed window so it could be an out of focus reflection of the lens, the tint coming from some interaction of glass/lens coatings.
--
Cheers 
Dave.
Reply to
Dave Liquorice
Could it be ligt leaking into the camera? see if shining light on the camera or shading it has any effect.
--
umop apisdn
Reply to
Jasen Betts
I'd expect that to be a streak from a small source or a broad streak from a more linear source. This a diffuse pinkish tinted circular area centerd in the frame.
--
Cheers 
Dave.
Reply to
Dave Liquorice
I would say it's a function of cheap plastic lenses at curtain angles within the lens and wave lengths of light. Try another lens - if you can ?
Another Dave ...
Reply to
Dave
"curtain angles" seems to be a misspelling for "certain angles". My search for this term, to make sure it wasn't simply one I was unfamiar with rather than the misspeling I suspected it was, led me to a wiki article on the subject of cameras which held my attention for an enjoyable 20 minutes or so.
Good idea, but as you pointed out, only if it's possible to fit another lens that can be adjusted to compensate for varaition in focal length.
Such cheap miniature cameras use a lens mounted in a small tube that is threaded onto the body, typically with thick silicone grease so it can be screwed in the required amount to satisfy the focussing condition with the silicone grease acting as 'locking compound' to hold the adjustment.
I'm not sure but there's probably a limited number of standard thread mounting sizes used in this class of camera so it might not be quite so hard to find another lens (usually canabalised from a scrapped miniature camera or else borrowed off another working camera) If the camera manufacturer offers a choice between wide angle and 'Fish Eye' lenses you may even be able to opt for a higher spec lens.
--
J B Good
Reply to
Johny B Good
I wonder if it might be worth trying a polarising filter.
Reply to
Rob Morley
Yes, I should pay attention to auto spell check !. One thing that would almost certainly check to see if it's the lens, is to remove the lens and place a piece of white paper over the hole and eliminate it from behind and see then if is it still has a pink tinge in the centre then.

Reply to
Dave
Disable that damn spell checker[1] :-\ _______^^^^^^
An excellent idea! (why didn't _I_ think of that?). At least you'll know whether a replacement lens will be worth trying or not _before_ spending any more money and/or time on a more permanent fix.
[1] I figured you meant to type 'illuminate'. I'll happily accept another 'auto spell check cockup' excuse for this one ("Once is an accident, twice is a coincidence...") :-)
--
J B Good
Reply to
Johny B Good
Probably bugger the camera. This a Pi camera module, if you are really careful it might be possible to unstick the lens but it's a bit risky.
--
Cheers 
Dave.
Reply to
Dave Liquorice
Might be worth attaching a (small) piece of paper so its sitting on the front of the lens, putting it where its lit by bright, diffuse daylight and seeing it it still shows the pink patch. At least that should tell you if the problem is external or internal to the camera.
--
martin@   | Martin Gregorie 
gregorie. | Essex, UK 
 Click to see the full signature
Reply to
Martin Gregorie
And if you do find a pink tinge on the white paper when you eliminate from behind, do see a doctor. It could be something serious.
--
--------------------------------------+------------------------------------ 
Mike Brown: mjb[-at-]signal11.org.uk  |    http://www.signal11.org.uk
Reply to
Mike
Also now being more sober, I've turned OFF auto spell check - It's really funny to look back ... Did I really type that - don't really remember that well !.....
Reply to
Dave

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.