Quick question about IR cut filter and true day/night cams

[photys 0]

"True day/night" cams have IR cut filters.

 

If you are not using IR lighting, is there any reason to get a camera with IR cut filter.

[rory 0]

Yes.

 

There is also IR in the daytime. Without an IR Cut Filter, the camera will always pick up IR Light, which means the daytime colors will look washed out. Most color only cameras will have a fixed IR cut filter. If they dont then they are one of those really cheap $30 cameras.

 

I know you've seen these

http://www.cctvforum.com/viewtopic.php?t=6122

[jisaac 0]

eleborating on what rory said:

there is a whole lot more light around us in the day than we see. But the camera picks it up. Thats why if you did not put the ir cut filter in front of the imager then it would be a useless picture. The difference in true day night cameras and a cheapo is this

 

"MECHANICAL ir cut filter"

 

but we have beaten this horse to death

[photys 0]

Got it. Thanks again guys.

Its not a true day/night cam if theres no cut filter. Thats the mantra of the forum

 

Why am I confused? :

I kinda assumed ther would be a cut filter on all midrange brandname outdoor cams.

 

0.3 lux + WDR + No Cut filter

http://www.samsungtechwin.com/product/pro_view_eng.asp?pro_uid=546&cat_uid=16&cat_biz=CTV&cat_lev=AC

 

0.7 lux + Cut filter

http://www.samsungtechwin.com/product/pro_view_eng.asp?pro_uid=1513&cat_uid=16&cat_biz=CTV&cat_lev=AC

[jisaac 0]

you are still a little confused.

all color cameras have a ir cut filter. They come standard.

 

Now your true day night camera will mechanically move them from in front of the imager in low light.

 

the only manufacturer that is straight forward on this issue is panasonic.

 

ex.

http://catalog2.panasonic.com/webapp/wcs/stores/servlet/ModelDetail?displayTab=O&storeId=11201&catalogId=13051&itemId=102543&catGroupId=14459&surfModel=WV-CF294

 

""Day/Night Feature (Chrominance signal is removed to achieve B/W image (no IR filter shifting))"

[photys 0]

Now your true day night camera will mechanically move them from in front of the imager in low light.

I thought the IR filter was removed from the imager in low light?

 

Patience of a saint isaac, cheers.

[rory 0]

Now your true day night camera will mechanically move them from in front of the imager in low light.

I thought the IR filter was removed from the imager in low light?

 

Patience of a saint isaac, cheers.

 

Yeah thats what he said, "move them from in front of .." meaning it will move it off the imager.

 

It cost more to have a moving IR cut filter and thats why those cameras cost more than the day nights that dont have it or just have fixed one.

[jisaac 0]

thats what I am talking about

the true day/night cameras will mechanically move the ir cut filter from out in front of the imager in low light.

 

didnt i say that?

[photys 0]

Sorry, I mis-read.

Didnt see the word "from"...... then used in in my post.

 

Thanks for the education.

[metafizx 0]

ok, for the cams that have no moveable IR cut filter, but have IR Leds, is the only difference the amount of IR that is filtered ?

 

in other words, "day night" cams with tons of IR leds (assume 840nm more visible spectrum) but NO IR cut filter, would just be a less light sensitive camera in darkness as compared to a cam with the IR cut filter ?

 

how much different is it ? (I know what someone will say "the difference is night and day" hahaha)

 

reason I ask, is I am currently looking for a good performer cctv cam that is low cost, with decent IR. There is some spotty lighting in a parking lot.

[rory 0]

one doesnt filter the IR at all in the day, the other does.

 

Normally they are cheaper cameras, and therefore less sensitive because of that. They dont filter IR at all.

 

But there are exceptions to the rule, except there is one rule that always stays the same, you get what you pay for.

[jisaac 0]

if you want to keep cost down then add some additional lighting outside and that way you wont need day night cams. There for no need for mech ir cut filter and ir's

 

hey but wheres the fun in that?

[rory 0]

^--- agreed

[metafizx 0]

if you want to keep cost down then add some additional lighting outside and that way you wont need day night cams. There for no need for mech ir cut filter and ir's

 

hey but wheres the fun in that?

 

geez, I get a headache swimming in the sea of all the cameras available.

so many and probably a lot of them are junk. just hoping for that "awesome" one that is not expensive.

 

I agree you get what you pay for...it's just the customers set a budget and think you can do it for $cheap. but I know the good stuff costs dough.

 

of course they want all the features too: hi res, "see license plates" from 80' feet away, battery b/u, and day/night viewing...networked DVR to record for a month, all on a $1500 budget (including internet configuration as well).

[jisaac 0]

ya i had the same issues with customers and so i took a different approach. now from the very beginning i tell them that I will be the most expensive proposal they will get. That way they are not suprised and I weed out the 1,500 dollar people before I waste any time.

[scorpion 0]

Ditto!

 

I want to prequalify my customers! I hate wasting my time doing a show, and tell, and then have someone turn around, and buy a system somewhere else that uses phone plugs for the wiring.

 

When I spot these tire kickers, I give them advice on what to look for. I know they are not going to buy from me, but when they call me down the road for an upgrade at least they bought bnc products.

 

I tell them that I am the most expensive as well. I want to make sure they have a need, and that they appreciate service, more than price.

[SBTVideoman 0]

Just to add more food for thought...

 

Rory (and others) have already mentioned that sunlight contains lots of IR which will cause washed out colours with any camera that has an IR-pass filter - common on many "IR LED bullet cameras" but also a feature of some full-body 1/3" cameras, especially those coming out of SE Asia. NOTE - many of these will state something like "IR-extend" on their specifications or have spec simlar to "0.1 lux @ F1.2, 0 lux under IR"

 

You can run into problems when using such camera inside under mixed ligthing....

 

Think about the two most common types of lights used inside in typical applications like nightclubs, hotels, motels, shops etc.

 

1) Fluoroescent tubes....these are a "cold" type of light in the sense that they produce only visible light.

 

2) Incandescent bulbs (either halogen downlights or the classic lightbulb invented by Mr. Edison) ...which are a "hot" type of light...that produces IR as well as visible...think about it....you're passing electric current through a metal filament...filament gets very hot and starts glowing....which is why incandescent lights are so damn inefficient, since most of the energy is turned into heat...some of it is smack bang in the 830 - 1500nm spectrum that IR sensitive cameras can see.

 

OK..enough about the physics....what does this mean in practice..?

 

I have seen video footage pulled off many a DVR that shows a person walking through a lobby in a hotel....and let's say they're wearing black clothes..and the camera used is an IR-sensitive colour camera (Ie NOT a true day/night unit with a mechanical IR cut filter)....and the person passes from under a fluoro light to under a halogen light...and hey presto you see their clothes turn from black to a green/turquise/aqua/teal colour....purely because as they walk under the halogen downlight, they are suddenly illuminated by both visible light and IR and the camera cannot cope with the mixed lighting.

 

Moral of the story - if you want 100% accurate colours...don't use an IR-extend camera...you're better off with a true colour camera that has an IR-cut filter or a true day/night unit.

 

TIP...with a full-body camera you can usually tell if the filter is an IR-cut or an IR-pass one. The true IR-cut filters tend to be a sea-green glass...with no sheen. The IR-pass variety tend to be an aqua colour with a strong pink dichroic sheen that's visible if you make the filter reflect some daylight. Hope that makes sense...happy to e-mail you some photos of the two filter types.