Webcam outdoors = overexposure

If the camera has no exposure settings or automatic exposure control, the easiest solution may be a neutral density filter (sunglasses).

You want a DIY solution? Get a pair of cheap POLARIZED sunglasses. Mount one in the normal orientation in front of the camera lens (maintaining original orientation is necessary to eliminate glare). Mount (tape or whatever) the second lens over the first, but rotated enough to reduce the light coming in to an acceptable level. Simple, cheap cross-polarized variable neutral density filter.

Anyone seen a diy solution to why webcams will produce whiteonly pictures outdoors?,

If I put a bit of cardboard in front of the camera and only allow light in for short moment. Image quality improves.

One idea would be some kind of small tft/lcd screen in front of the camera. What would allow light in synchronised with the image download. I know there is at least some welding protection that works this way =)

There is ofcourse videocameras that does this, But I would like some better resolution. And fps doesn't matter too much.

This is a huge effect since the solar spectral intensity of IR, e.g. at 1 micron is nearly 1/3 the maximum (I believe in the green?) and the CCD sensitivity is close to 1/4 maximum. what you want is IR and UV blocking filter. I haven't found a cheap one yet. Let us know if you find one. Lyle

I suspect the exposure time is fixed ;) I wondered if it could be fixed externaly somehow. But maybe it's possible to fix with sw. I thought webcams in the lowend didn't have exposure control. But rather assumed room lightning with bulbs all the time.

The problem may have several causes:

- Usually every webcam has exposure control, but it works only electrically and can't prohibit overexposure of the sensor pixels in extreme light. For a real exposure control you need an adjustable iris, but that's too expensive...

- Direct sunlight isn't properly shielded by the black mask on the sensor chip and disturbs the signal processing circuits (shifts bias etc).

- Sunlight has a high IR component which gets through the cheap IR filter (usually done by coating on one of the lenses) and makes the image unsharp and dull.

I'd guess the webcam is broken.

The ones I tried are not very sensitive to begin with, and seem to regulate by changing the exposure time. The el-cheapo Logitech I have here can hardly be overexposed with any daylight source or powerful lamp. It *can* be underexposed easily however :-(

Note that the various "automatic" settings need to be invoked. Sure the settings are not "fixed" (exposure time etc)?

Oh but the exposure time is fixed. It's just that it uses more than one frame to cope for the lack of light. Hence, if it is very dark the animation is not smooth at all.

Even the cheapest of the cheap webcams (like my E20 Logitech) has a "camera settings" posibility, allowing the exposure, brightness, contrast etc to be set. usually the default settings will do.

I can point the cam overhere directly at a halogen desk lamp, and it will even show the filament after some adjustment time.