how to focus a CCTV camera

[JeffCharger]

I have a number of CCTV cameras with a variable lens (3.5-8mm), that have a lens set with 3 setting/rings. They are labelled:
1) near - far
2) open - close
3) T - W

I tend to have a couple of problems:
1) the center of the picture is in focus, but the outer edges are out of focus
2) in sunlight, the picture is washed out a bit (not completely, but not as clear as other cameras)

What's the best way to get these things focused? I can't seem to get the right combination of settings. Is there a set of steps of which to do first? (e.g. distance first, then open/close etc.??)

 

[jhdale]

Do those happen to be Rainbow lenses? Sounds familiar. You have to adjust zoom (T - W) before focus (near - far), and the two interact (i.e. changing the focus also changes the zoom somewhat) so you may have to go back and forth a bit.

Having part of the image in focus and part out could just require adjusting the focus better, but it could also be a depth-of-field issue (things that are too close/too far are out of focus). I believe narrowing the aperture (open-close) will help.

Narrowing the aperture (adjust open-close towards close) will also reduce the amount of light reaching the sensor, which should reduce the degree of wash out since that comes from getting too much light. This may also depend on whether you have an automatic gain setting on the camera (which you want since light level will be changing).

 

[gatchel]

Is there a back focus adjustment on the camera?

 

[JeffCharger]

thanks for the responses.... here's an example of what I'm suffering from. The camera is getting a lot of sun (not directly into the camera, but in the viewing area of the picture.)

What adjustment is necessary to improve this?

 

[gatchel]

At first glance it looks like the image is getting washed out due to the bright sunlight. There really isn't much other than BLC (backlight compensation) and ALC (Automatic Level Control) that could help. I really don't think you are going to be able to resolve the issue or at least make it better unless you use a quality Wide Dynamic Range Camera (WDR). If you are able to make adjustments you may affect night time viewing.

You may want to try repositioning or reloacting the cameras to a location that sees a more consistent picture.

Your image may still be a little out of focus, it's hard to tell at 320X240

 

[ano]

I have a number of CCTV cameras with a variable lens (3.5-8mm), that have a lens set with 3 setting/rings. They are labelled:
1) near - far
2) open - close
3) T - W

I tend to have a couple of problems:
1) the center of the picture is in focus, but the outer edges are out of focus
2) in sunlight, the picture is washed out a bit (not completely, but not as clear as other cameras)

What's the best way to get these things focused? I can't seem to get the right combination of settings. Is there a set of steps of which to do first? (e.g. distance first, then open/close etc.??)

I don't know what cameras you have but I can tell you outdoor camera applications are about the most difficult camera application that exists. The camera has to operate in the cold, in the heat, in the sun, at night, through rain and snow, and still focus on anything everywhere perfectly. This is one area that you get what you pay for, and your not going to get a $1500 picture from a $200 camera. A good lens alone with good outdoor contrast can cost several hundred dollars. You should be able to adjust focus, but the other problems can't be adjusted away. Set telephoto - wide zoom first, then focus.

 

[mustangcoupe]

I would try first the open/close ring to cut down on the amount of light but that will impact your low light picture. Then adjust the near/far ring for focus.

 

[gatchel]

I would try first the open/close ring to cut down on the amount of light but that will impact your low light picture. Then adjust the near/far ring for focus.

Good point. I didn't even think to go there. I haven't installed anything but auto iris lenses in the past 10 years...