Shutter Speed

[grumgukenhoff]

Hi, I am using a Geovision GV800 cctv system and most of my cameras are analogue. I recently got a 1.3 megapixel camera installed..it is a GV Cb-120 and all is fine except there is a setting to adjust the shutter speed...it's reasonably ok on "Auto" but much better for movement on "Auto (High Shutter Speed)...problem is when I put it on this setting I am getting interference on the picture.similar to the kind of interference you would get with a bad connection (lines across the screen..that kind of thing). I wonder is there any way around this please. Any help would be appreciated.

 

[wxman]

Hard to say for sure without seeing an example, but I would assume that what you're seeing is "low light noise"....That is, the sensor needing more exposure in order to receive enough light to make a clear image. The higher the shutter speed, the less light the sensor is able to receive, thus the more subject to low light noise the image will be...I'm assuming that there's no aperture adjustment (or either the cam knows to keep the aperture wide open in low light), in which case a slower shutter speed would be the only option for decreasing the noise under current lighting conditions. The other option would be to add more physical light (visible or infrared) to the scene.

 

[nayr]

its called gain, you crank up shutter speed expect gain to go up too to maintain the same contrast.. or else the image will be darker because the amount of light your letting get through is much less.

for example my license plate camera has very high shutter speed (1/1500) and very low gain.. the image is completely black without a star visibly burning 7mins away.

I can crank the gain way up and start to make out objects in the dark, but then the plates are so full of noise you cant read em.. there is no other way to get sharp images of plates going by at 45-50mph.