Started with a MS VX-6000 webcam.  Was able to remove the IR filter without breaking it using an exacto knife.  I’m now using 2 fully exposed film negatives as an IR pass filter.  Below are pics from the webcam. 
Is this too much visible light?  I’m out of negatives, so should I just buy a real filter?  You can see that the camera is picking up the Infrared line on the CD which is produced by an 850nm laser with a line lens.  The line is not visible to the eye.

Looks like you need more filter material OR the light source in your room has a lot of IR OR you shot that in a room with sunlight IR filtering in.

Tinkerman - 22 June 2008 01:42 AM

Looks like you need more filter material OR the light source in your room has a lot of IR OR you shot that in a room with sunlight IR filtering in.

You’re right too much sun.  Not too bright of me (no pun).
Thanks.

have u tried the floppy diskette? i tried the film method and me too was getting too much visible light… in the end i used one floppy diskette

I was going to post a new topic but since it was already mentioned in this thread, i’ll post my question here.  Which method do people find works better: the photo negative or floppy disk?  Also, does it matter if it is black and white or color film?

stargazer424 - 23 June 2008 11:44 AM

I was going to post a new topic but since it was already mentioned in this thread, i’ll post my question here.  Which method do people find works better: the photo negative or floppy disk?  Also, does it matter if it is black and white or color film?

It depends on the camera and setup. You should try both or combinations until you find what works for you.
Exposed & developed color or B&W film will work.

Great! Thanks Tinkerman! I’m at the very begining of my project. Going to start with an MTmini. No current plans of creating a whole system. I just want to play around for now.

So rdagger, did you find that the 2 pieces of film worked well for you? (minus the sunlight)

stargazer424 - 23 June 2008 03:03 PM

So rdagger, did you find that the 2 pieces of film worked well for you? (minus the sunlight)

It works, but I think I can do better.  I ordered an 850 nm IR pass filter on eBay for $8.  I will also try the floppy method and let you know my results.

I’m very curious to find out how that works for you rdagger.

Tinkerman - 23 June 2008 05:22 PM

I’m very curious to find out how that works for you rdagger.

It did not work.
Here is my review.

so pass filter != bandpass filter?

Nope…
highpass filter - passes high frequencies
lowpass filter - passes low frequencies
bandpass filter - passes a specific frequency

I’ve found in optics that low-pass and high-pass are often called long-pass and short-pass filters.
The filter that you need to remove from web-cam is called a short-pass because it allows visible light but blocks IR (opposite of long-pass).  It’s also called an IR cutoff filter.  Long-pass filters are also called UV cutoff filters.  They pass visible and IR portions of the spectrum, but block the UV portions.  Bandpass filters are also referred to as interference filters because they reduce interference from unwanted peripheral radiation.  These are very helpful for MT applications.  I’ve had the best luck with narrow bandpass interference filters.  There are also broadband interference filters.