Invisible lights at DVinfo.net

November 23rd, 2002, 07:35 PM

Just a thought, most of us know that a camcorder will 'see' the invisible light from an iR remote control. (I mean optically you can see it through the viewfinder). It follows that if you had a light that projected that wavelength, maybe you'd be able to shoot people unobtrusively. (Most people don't like a light stuck in they're face). Or maybe that's how some of the 'low light' cams work.
Andy
Imagine newmedia

Andre De Clercq · November 24th, 2002, 04:44 AM

You're right. Some lowlight cams have their IR blocking filter removed, for higher IR sensitivity, and have IR lightsources build in. Keep in mind that colorvideo isn't possible and in most cases the optics (mostly wide open) are not optimized for IR imaging reducing image sharpness.

Mike Rehmus · January 9th, 2003, 08:43 PM

If you could see a response curve for silicon-based detector to different wavelenths of radiation, you would see that the IR sensitivity of a detector is almost 2X for that of light in blue end of of the visible spectrum.

I would believe that most cameras have an IR filter in place unless NightShot is turned on. The IR filter looks like a piece of lightly dyed blue glass that is attached (on most cameras) directly on the face of the CCD.

IR images look just like IR film except they are frequently green in a camcorder.

Back in the early 80's when we were making the first digital cameras, we had to buy IR filters to place on the front of the lens to keep the cameras under control.

November 23rd, 2002, 07:35 PM	#1
Andy Wason Posts: n/a	Invisible lights Just a thought, most of us know that a camcorder will 'see' the invisible light from an iR remote control. (I mean optically you can see it through the viewfinder). It follows that if you had a light that projected that wavelength, maybe you'd be able to shoot people unobtrusively. (Most people don't like a light stuck in they're face). Or maybe that's how some of the 'low light' cams work. Andy Imagine newmedia

January 9th, 2003, 08:43 PM	#3
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	If you could see a response curve for silicon-based detector to different wavelenths of radiation, you would see that the IR sensitivity of a detector is almost 2X for that of light in blue end of of the visible spectrum. I would believe that most cameras have an IR filter in place unless NightShot is turned on. The IR filter looks like a piece of lightly dyed blue glass that is attached (on most cameras) directly on the face of the CCD. IR images look just like IR film except they are frequently green in a camcorder. Back in the early 80's when we were making the first digital cameras, we had to buy IR filters to place on the front of the lens to keep the cameras under control. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

November 24th, 2002, 04:44 AM	#2
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	You're right. Some lowlight cams have their IR blocking filter removed, for higher IR sensitivity, and have IR lightsources build in. Keep in mind that colorvideo isn't possible and in most cases the optics (mostly wide open) are not optimized for IR imaging reducing image sharpness.