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jisaac

lights which cause problems

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Here is a question I have for you guys who have experience in installations.

Which type of bulbs do you think causes the most problems in your camera shots? This is purely your opinion. Just would like to know what your experience has been and if you can describe the image problems.

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any light, back light, or light reflected. ie. a storage room with a garage door that is opened and closed or remains opened......the light coming thru that garage door creates the problem. Solution; mount the camera higher than the top part of the door and set dips/osd's properly to compensate for the changes. ie. light at night that reflects off of the housing lense or dome cover that creates a halo effect. solution, mount in an area that eliminates reduces the reflection. ie. ir reflection. solution, take the sun guard off.

 

and the number #1...clean the freak'n camera and/or enclosure. Light reflects MORE when it 's dirty.

 

I guess I'm trying to say that if you don't anticipate the problem of light issues (natural or man made) you will have to live with the problem or reinstall. Most time this problems is not a big issue as I have not seen it all that much.

 

Light is my friend in my world of camera's

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thats not really what I am talking about.

I am talking more along the lines of particular light bulbs that put off a spectrum of light that was not anticipated that the camera obviously see's.

Of course light is your friend other wise we have no images. Unless we all used thermal. Sales would probably go down. Anyways back on subject.

ex.

***** light bulbs/

***** lights used for _________________

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Ya one of the easiest ways to tell if someone is a newbie that installed a system is it seems they always mount the camera right behind a flourescent light looking right into the light. At least around here. Its pretty funny.

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Any High Pressure Sodium Lamps usually will cause poor color reproduction. Especially with cheap cams. I wonder how the SDIII would do in a warehouse type environment with HPS lamps.

 

40946_1.gif

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Good question jisaacmagee.

 

Pulled this off a website which shows the color rendering index (CRI) which is a measure of how accurately an artificial light source displays colors as this is always a challenge for us. And when there is an incident you want to correctly identify an individual. Did the "client" have a yellow jacket or a brown jacket.

 

41012_1.jpg

 

"CRI is determined by comparing the appearance of a colored object under an artificial light source to its appearance under incandescent light.

The higher the CRI, the better the artificial light source is at rendering colors accurately."

 

All too often we find the terrible low pressure sodium installed at sites (guess the bulbs are cheaper) With government buildings they are coming with increased lighting as it is a Health & Safety concern....employees walking to their cars....guards making patrols.

 

One of lights that bugs me is those bollard looking lights (3 feet) Hard to mask them out of the picture.....boy I hate architects

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The subject of lighting is complicated, not simply because of the Colour Temperature of an individual light source, but for a number of other factors.

 

Assuming the use of colour (color!) cameras, individual imagers will reproduce colours differently under a common source (for example daylight), and the cameras themselves will have highly variable 'White Balance' circuits which all help to create problems, even for the most experienced practitioners.

 

Optical lens filtering can help in certain situations, but I can't even remember the last time I've seen that applied in the field.

 

Understanding how a range of cameras will behave with different light sources, indeed often mixed light sources (e.g. daylight and fluorescent) is one of the hardest things to get to grips with. Unfortunately, whilst training and demonstrations can be useful, there realy is no substitute for experience.

 

Incidentally, the majority of problems I come across, are where little or no consideration has been given to the requirements for appropriate lighting.

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do you know what is amazing to me is around here people dont realize that the system that they had was not going to be effective (usefull video) until an event happeans and they find this out upon review. Man I am so extremely meticulous in each camera that I am still making sure the camera is adjusted way after the customer ok's it. A couple of weeks ago I got suckered in to doing a an install on saturday for a guy that I grew up with. And of course he was having us install an existing system in his new building. (not our equipment). Well that same weekend he got stuff stolen from his back area where he parks his trucks with equipment in it. I am not sure of the type of light that was out back but it was one of those huge bubls that puts out a peach color and it rained that night so the light was intisified off of the wet pavement and you could see nothing. the cameras were cheap bullets and I got to say, "sorry, thats what you get with sorry equipment". The cameras were just blinded by this light that was not that bad. I would like to get a better knowledge of exact lights and their names and how they affect your picture.

try to deal with things before your "dealing" with them.

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While doing some research sometime back, I read an article that said sodium light had the most adverse effect on color cameras.

 

I also researched light sensitivity and the other specs. From there, I went outside to compare what the naked eye could see in comparison to my average priced low lux cameras without IR.

 

It looked to me that -sodium light - alters color to the naked eye as well. If you really think about it, sodium light seems to change the tint of most colors.

 

I also noticed that the modern low lux cameras are more light sensitive than the naked eye.

 

Just thought I would through that in for something to think about.

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