I have a digital camcorder (a JVC GR-DV500 w/ a 38mm lens) without ‘night vision’ capability.
Is ‘night vision’ a hardware requirement, meaning it would be something impossible for me to achieve with this camera, or can I buy something to add-on to it – like a filter – that will yield this result?
Also, I once read (can’t find the cite, sorry) that camcorders pick up not only visible light, but also IR light by design. If I used used an IR flashlight or something, would it work as night vision?
It’s likely that the camera contains a built-in filter that reduces the IR hitting the lens. So the IR flashlight won’t work.
You can test the sensitivity to IR by aiming your TV remote control at it and seeing if it picks up the emitter at all.
And yes, there’s probably hardware enhancements that you need to get decent low-light capability – if nothing else, cameras with this feature probably really crank up the gain (as well as having IR filters that flip out of the way).
The pickups used in camcorders are very sensitive to near infrared–the final stage before the CCD typically includes a filter that keeps the ambient IR down to a manageable level, although a bright emitter (like a remote) shows through clearly. The filter is generally such an integral part of the lens assembly that you can’t remove it without seriously compromising focus (at best).
That said, I did manage to modify one some years ago by replacing the filter section with plain glass. I used a bank of IR leds as an illuminator, and it worked pretty well, though the images were never as sharp afterwards.
They could make the cameras work with IR illuminators easily by leaving out the filter, but it would interfere with the cameras’ intended application in normal light–there’s a lot of ambient near-IR, and it would wash out the images. I suspect it would also reduce the life-span of the pickup, but I’m not sure.
It would cost more to make the filter switchable, but it could certainly be done. There apparently hasn’t been enough demand for such a feature for the manufacturer’s to bother with it, though.
A final note–the modifications described above wouldn’t make a true night-vision camcorder, just one that could be used with an IR light source. True night vision would require the addition of light-intensification hardware and/or a different pickup (CCDs aren’t as sensitive to thermal IR, so thermal imaging would require major changes).
Try taking your camera and your TV remote into a totally dark room. Use the remote as a flashlight, and see if the camera can “see” the objects it shines upon. If this works, then your camera is already fairly sensitive to IR light, and all you need is one of those infrared spotlights sold by security camera outlets (the ones whcih are made up of clusters of super-bright IR LEDs)
Another thing to try: find a theatrical supplier and buy one sheet each of “Congo Blue” and “Primary Red” filter gels. Cut out some pieces and cover your camera lens with them, using two or three layers of congo blue and one layer of primary red. Now go use the camera outside in the bright sunshine. If the camera still works, it will be seeing the Infrared world.
What about UV light? I’ve noticed my camera will pick up things that appear only in UV light (dyes, for example). Could this be helpful with any type of ‘night vision’?