jonandmarkuk Posted March 14, 2009 Posted March 14, 2009 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.
Guest RJBsec Posted March 14, 2009 Posted March 14, 2009 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.
Doktor Jon Posted March 14, 2009 Posted March 14, 2009 ... 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 ). 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.
jonandmarkuk Posted March 14, 2009 Author Posted March 14, 2009 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 ). 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.
georgahti Posted March 15, 2009 Posted March 15, 2009 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.
jonandmarkuk Posted March 15, 2009 Author Posted March 15, 2009 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.
georgahti Posted March 15, 2009 Posted March 15, 2009 then just retune the "halo"ones with the monitor.
jonandmarkuk Posted March 15, 2009 Author Posted March 15, 2009 then just retune the "halo"ones with the monitor. 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.
georgahti Posted March 15, 2009 Posted March 15, 2009 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.
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