Updated 2004-07-28: added pictures in sun light.
I have three different Logitech QuickCams, two Expresses with HDCS-1000 and Photobit sensors, and QuickCam Web with VV6410 sensor.
I noticed that they behave quite differently with different light sources, so I decided to make a little test by taking a snapshot using three different light sources, a normal light bulb, fluorescent light, and a special ultraviolet lamp designed to tan.
Here are the results. From left to right, there is first a normal light bulb, then the sunlamp, then the fluorescent light, a picture with both fluorescent light and the light bulb turned on, and finally a picture taken in real sun light, coming from a window.
The round cocktail stick container had very red cap and label. The hearing protectors are deep blue. The calendar in the background had pure white in the lower part and green forest picture in the upper part.
In all cases bilinear interpolation was used for converting Bayer images from camera into RGB. This corresponds to "best" quality in qc-usb 0.6.0 or to "bilinear" in newer versions.
The results could be likely improved by using color balancing with software (-g option with qcset). Also the driver allows adjusting color balance using hue and saturation controls somewhat with the HDCS sensor. It would be nice also to have a picture taken with real digi-cam from the objects for comparison, but I don't have one.