You know how you are supposed to use negative film strips and a camera to check to see if your filter is working? Well, i just bought a new laser, and the person that sold it to me said that it did not come with a filter, so i check, and it isn't working. Negative film strips are the ones that you buy at rite aid for a camera right? well i point the laser at the strip, and then i look at the wall with my camera, and i don't see anything. So i try with my webcam, and that doesn't work either, can someone please tell me what to do.
LPF Donation via Stripe | LPF Donation - Other Methods
Links below open in new window
ArcticMyst Security by Avery
IR filter testing?
- Thread starter Vedant002
- Start date
- Joined
- Oct 26, 2007
- Messages
- 5,438
- Points
- 83
Those negative film strips will block your green light and pass some IR through, while absorbing some as well. You can't see that IR with your eyes, nor do you really want to. You'll need a digital camera to see it, and most decent ones will have an IR cut (blocking) filter in them, so you won't see much from them either.
If you really want to see the IR dot, you'll need to get something like a webcam, open it up and remove the IR filter from it, and then observe the output using that instead.
If you really want to see the IR dot, you'll need to get something like a webcam, open it up and remove the IR filter from it, and then observe the output using that instead.
i cant see the dot with my camera? does it matter what strips i am using, my strips are just the camera film strips that i bought from rite aid, they do not say negative film strip on it though. Do i have to get one that say "negative film strips" on it?
- Joined
- Oct 26, 2007
- Messages
- 5,438
- Points
- 83
Well does your camera have the IR filter removed? If not, you won't see much IR unless the source of it is very strong. Also, those negatives are usually used for putting in front of the camera, not the laser, to block out visible light like a real IR filter (only not as well). In fact, you'll probably need to keep the filter on the camera anyway, so that the visible light doesn't overwhelm the IR light you detect. Still, I've never found that film negatives really work that great, because they're so lossy.
