IR 840nm Filter

[rory 0]

They say dont touch it .. is it safe to touch, this may be a silly question but just checking .. i mean is it just an issue of dirtying it ..?

 

Also, is it safe to look through .. the human eye i mean .. just want to check it out .. i have one here .. may test it with a camera in daylight full sun out, to see if focusing like that may be better so that it stays focused for the IR at night ..

 

thanks

Rory

[Jasper 0]

Probably don’t want you to get it dirty so you can get the full effect.

 

It don’t think it is to lessen your exposure to Radiation, but maybe they thought about the guy who would put his eye next to it.

 

As far as using it in the sun, well your Rory your just plain crazy.

 

And I like that about you.

[C7Installer 0]

Whle I'm not familiar with IR filters, there MAY be another reason not to touch it. For example, halogen bulbs get VERY hot when they're on. You're not supposed to touch those because the oil from your fingers can cause the glass from the bulb to heat unevenly, which can cause the bulb to fail (crack or explode). Perhaps this is the case with IR filters as well? Or, maybe not. Just an idea...

[Cooperman 0]

If the filter is 'dyed in the mass' glass, then there's no problem handling it. If it's a dichroic filter, then the coating on the glass may be easily damaged.

 

With both types, you should never look through the filter at a bright light source for any length of time. Although the human eye is not capable of imaging with Infra Red at this frequency, prolonged exposure could damge the retina, and it's not reversible

[rory 0]

i looked through it

[Cooperman 0]

What did you see .....?

[rory 0]

the light was red ... the camera doesnt see anything through it though as its really a mirror type filter ..

[Cooperman 0]

If it looks like a mirror, it's probably a dichroic filter with a coating bonded onto the glass substrate.

 

You can hold the filter right up to the lens of a b/w camera, and it should see straight through it if viewing under daylight or tungsten light sources.

 

As long as you don't spend ages staring at the filter with the lamp switched on, you shouldn't have any difficulties. You're far more likely to have problems coping with the bright sunshine in your tropical paradise

[DVR MAN 0]

Never look into I/R sources. The I/R causes cataracts to form in your eyes. Laser light also affects eyes the same, and some wavelengths can blind you. The invisible 950 NM wavelengths are extremely dangerous as you cannot see the beam and exposure is not cognizant to you at the time.

[rory 0]

Thanks ...

but why are you replying to a thread from 2005?

My eyes would already be fried by now

[DVR MAN 0]

I replied because this is a health risk. I work in the Laser industry and have been aware of this issue for years via product warnings. The amount of damage is dependent on the wavelength/power, etc.

[RickA 0]

Good info even if Rory can no longer see!

[Scruit 0]

I test IR filters with my IR emitter. If it's an IRCut filter then a cmera will not see the emitter (or a TV remote control emitter) through it. If it's an IR pass then you can still see the red glow of the IR emitter through it (and nothing else).

[rory 0]

ok thanks DVR Man, just checking.

 

and Rick .. LOL .. Ive been near blind for sometime anyways. I think its that age thing now.

[RickA 0]

Know what you mean Rory, at my age am lucky to be able to see the end of my nose!!!

[rory 0]

Back to this topic, was setting up an EX82 tonight in the garage (was raining).

Anyway, so garage is 20-25' in length, eyes hurting a little but otherwise look normal. Anyway, spent about 20 minutes or so doing that. Question for those that might know, does IR reflection from the wall (where i was pointing the cameras IR) react the same as visible light or as looking at the IR LEDs? Or maybe the monitor just was hurting my eyes (dark with bright image on the CRT).

 

And another question, can IR light from the LEDs burn the skin and does it contain radiation? Whats the risk of radiation, cancer, etc. of anything?

 

Thanks!

[zmxtech 0]

ex82's IR beam is very strong but its a grid of LEDs spaced out to give a nice spread. , all other IR cams job also is to spread the beam not focus it -tho they can get warm if your close

 

oh yes it will bounce if its the right color - IR can be strange

 

most LASERS need at least 100mw of power finely collimated to burn anything

just got a 100 and 400mW for testing.

 

All the IR LEDs I have seen spread the beam out so no burn !

 

but you should not stare into it of course thats just silly. I treat them like a LASER and keep at least a few meters away just incase....

 

my 2c

 

z

[DVR MAN 0]

Lasers are collimated by nature as the beam bounces between two mirrors at high frequency before exiting the device. The beam is co-linear (parallel waves). When viewed, the eye tends to focus on the beam on the retina. This burns the retina. L.E.D. radiation is non ionized radiation. Just below the microwave spectrum. It produces heat which is absorbed by tissue. Different tissue absorbs I.R. at a different rate. There is a specific absorption rate (S.A.R.) is determined by the frequency of the I.R. wavelength. Long exposure causes cataracts to form in the human eye from I.R.

The I/R and Laser can reflect. The angle of incidence equals the angle of reflectance.

[Lolo Wolf 0]

Safety (IR Devices)

"Extreme care should be exercised when working with

infrared illuminators. Illuminator should also be

powered down while being installed or serviced. The iris

of the human eye only responds to visible light.Looking

into a 500-watt infrared light source is like looking into a

500-watt light bulb without your iris closing to block the

light.The effects usually do not appear until hours after

the exposure.The effects are similar to watching arc

welding without eye protection. Mild exposure can feel

like you have sand in your eyes, severe exposure can cause

temporary or permanent blindness." ( brief from CCTV System Design and Installation NTC training Center)