Jump to content
Security Installer Community

Halo Effect With Ir Lights


jonandmarkuk

Recommended Posts

Hi

I have just installed a 4 camera CCTV sysytem using 4 verifocal cameras I got from Maplin.

I'm very happy with the daytime pictures from the cameras however at night I'm getting a strange 'halo' effect of light on 2 of the cameras and I can't figure out why.

I have tried moving the housing to see if it was too far forward and causing the IR to reflect but doesn't seem to have changed anything.

I could understand it more if all the cameras were the same, but when it's only 2 doing it I find it very strange, the only thing I could think is I did fiddle with the focus and zoom on 2 of the cameras, but as they all look the same I don't know which ones got put up where.

Link to comment
Share on other sites

Guest RJBsec

Are these all-in-one IR cameras, IR inside domes or IR inside housings?

IR lighting can reflect off of the glass/polycarbonate of doms/housings or off of water droplets and spiders webs.

Link to comment
Share on other sites

... the only thing I could think is I did fiddle with the focus and zoom on 2 of the cameras, but as they all look the same I don't know which ones got put up where.

Welcome jonandmarkuk :)

It sounds like you may have adjusted the lenses to give a wider coverage on the cameras showing the 'halo' effect, whereas the other two are on a more telephoto setting, so are effectively looking through the middle of the halo, which is therefore not showing ( don't know if that makes sense :unsure: ).

Generally speaking, a camera lens always needs to be as close to the glass / plastic window as possible to minimise reflections, or if that's not possible, an anti reflective dark tube or collar needs to be placed around the lens (i.e. between the lens and the glass), in order to restrict any light from actually reflecting onto the window and being seen by the camera. Unfortunately neither of these techniques can compensate for any internal reflections that may be set up within the glass / plastic itself, which is often a problem associated with either a 'dirty' or scratched window.

Link to comment
Share on other sites

Welcome jonandmarkuk :)

It sounds like you may have adjusted the lenses to give a wider coverage on the cameras showing the 'halo' effect, whereas the other two are on a more telephoto setting, so are effectively looking through the middle of the halo, which is therefore not showing ( don't know if that makes sense :unsure: ).

Generally speaking, a camera lens always needs to be as close to the glass / plastic window as possible to minimise reflections, or if that's not possible, an anti reflective dark tube or collar needs to be placed around the lens (i.e. between the lens and the glass), in order to restrict any light from actually reflecting onto the window and being seen by the camera. Unfortunately neither of these techniques can compensate for any internal reflections that may be set up within the glass / plastic itself, which is often a problem associated with either a 'dirty' or scratched window.

I think you maybe correct. I thought I had adjusted them all back to the same setting as each other but guess not :(

I'll have to go out tommorow evening to see if I can adjust them without altering the view too much.

Link to comment
Share on other sites

I think you maybe correct. ...

i've never heard him being wrong.

there might be other reasons as well but as we can not be 100% sure what you did with the cameras it is hard to say..

anyways it sounds like you just tuned them by heart - or did you use a monitor while tuning them? if you touch the zoom you need to tune the focus as well (and usually fine tune the iris) AND tuning them "always" needs a monitor so you can see how it affects the picture.

Link to comment
Share on other sites

i've never heard him being wrong.

there might be other reasons as well but as we can not be 100% sure what you did with the cameras it is hard to say..

anyways it sounds like you just tuned them by heart - or did you use a monitor while tuning them? if you touch the zoom you need to tune the focus as well (and usually fine tune the iris) AND tuning them "always" needs a monitor so you can see how it affects the picture.

I had adjusted them using a monitor, they look fine during the day. It's only when the IR turns on at night does the Halo effect happen.

To be honest the two which are fine are very likely to be the ones I manually adjusted.

Link to comment
Share on other sites

was planning on doing, but waiting till it gets dark as it will be easier to see when I have sorted it.

Being new to CCTV I wanted to be sure that adjusting the cameras was the correct thing to do.

adjusting is always correct. especially if you suspect the tuning being the reason it is good to start fault finding with adjusting the cameras.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.