Alright i’m building my first FTIR table, which I thought was going on without a hitch until my lens came in today.  I have the Phillips webcam I saw quite a few of you use, I then bought this http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280095957053

From what I read I thought this lens let all light in, in addition to normal light, which I would then have to filter out normal light so I would be left with IR.  However when I got the lens it is opaque, so I thought COOL It blocks everything but IR. 

When I hook it up to my computer though, all I get is a dark picture.  If I hold up my tv remote right up to the lens, I faintly see light.(IR LEDS are not here yet).  What am I missing????

Thanks,
~Carl

I have the phillips webcam, and that lens from that seller.

Assuming you havent accidently adujsted your webcam seetings it sounds like you got sent a wronge lens.  My lens does let in all light, if you use it in daylight the image is whited out.  So you have to buy a filter that blocks visible (i’d reccoment one that doesnt let any light under 800nm in)

*edit* gave out a serial number for the wrong lens!

It came in a little baggy that says 04318NDB 4.3MM F1.8 .  So I’m guessing I got sent the wrong Lens… that is the correct Lens I ordered right?

Yeah got it a while ago though, so it might be different stock etc but that looks like the one i got more or less (different F rating though?).

Email the seller, and ask if he sent the correct one etc.

See if you can test out this lens on an FTIR setup, it might block visible light and it might work!

Just to double check.. this is at least what it looks like

http://www.flickr.com/photos/13407352@N00/444341161/

Maybe you have the lens cap on still?  It is very snug.  The lens should *not* look opaque and bumpy.

Oops i gave out the serial number for a different lens, i bought an adjustable focus lens and i gave you the serial number for that.

and i think xsvdo is right… the lens cap is on…

wow....  Its a cap.... 

It obviously looks like a cap now..  I thought it was some kind of filter, seeing as IR goes through it in a limited amount (ok there is no redeeming myself for this one)

Thanks for your help

lol, okay good that you at least have the right lens

I have this exact same lens from that seller, the 04318NDB 4.3mm F1.8 lens.

When I hook up the lens to the philips, the images (when viewed in standard mode) produced are incredibly blurry/unviewable with conventional webcam software. Is this an intended consequence to make the IR reception less effected by non-IR objects?

Thanks!
cmoski

Edit: I was playing with a few filters in directshow and found my problem to be in my own code.

Please ignore my insane ramblings

hahaha...this is the funniest walkthrough ive read yet!

:D

ROFL.. Without a doubt.. It’s bandwagon stupidity at it’s best, but really funny!