Re: Flicker in QuickCam? Whose fault?

Steve Loboyko (slob@mindspring.com)
Wed, 22 Feb 1995 23:44:15 -0600

>ko@komac.knoware.nl (Ko Stoel) said:
>>
>>CU-SeeMe, QuickPict, QuickMovie all suffer from QuickCam not being accurate
>>at it's exposure time. Every once in a row frames differ in brightness.
>
>Connectix responds:
>
>European countries do not tend to use incandescent lamps like we use here. They
>use flourescent and halogen and a variant of incandescent, all of which pulse.
>Moreover, the European power frequency is 50Hz, not 60Hz, which means that
>flicker from light sources tends to drop down into the 1/100th of a second
>level, which is about what QuickCam is set at for normal lighting conditions.
>
I have noticed this phenomenon with my CCD cameras (not QuickCams), also. I
beat it with the following 2 "fixes"

1. A desk lamp, incandecent, shining at the subject, who hopefully takes up
a good part of the screen. But I have not noticed significant flicker from a
halogen desk lamp.

2. Infrared LED's (one of my cameras has no IR filter). This trick will not
work on cameras that have IR filters, (I think the QuickCam does).

The way these auto-everything cameras work, they can be fooled by
backlighting, making the flickering on the important subject (i.e., your
head) more pronounced. The cameras are easily capable of getting sufficient
light for a close object from the monitor, which flickers a lot.

________________________________________

Steve Loboyko
Software Engineer
cR Solutions, Incorporated
11285 Elkins Rd Suite G-1
Roswell GA 30076

slob@mindspring.com
http://www.mindspring.com/~slob/home.html

________________________________________