Cameras really block IR?

Question

i took a remote control, aiming at my camera and look at the LCD screen on my camera. my camera sees the IR light from the remote control. but it seems that almost all cameras, my phone camera and web cam, they all take in IR.

i read from some places that devices like web cam, they sometimes block away IR with some filter. but why do cameras block IR?

it seems to me that most camera devices, camera, handphone and web cam, they all allow IR to go in.

Answer 1

Yes, a lot of cameras are sensitive to IR. It's a function of price. The cheaper end of the camera spectrum doesn't filter out IR. On those cameras it's also not usually necessary to filter it out because the quality of the images isn't optimal anyway so the chances are that it won't be noticed.

As you move up the cost scale to the high end SLRs, these usually do filter out IR aurpmatically because when you're spending that kind of money you expect perfect images and you can usually tell the difference too.

The problem with IR is that it can adversely affect your exposure and the sharpness of your images. The effect is small and usually not noticed by amateurs and definitely not noticed if you have average or lower image quality.

However if you can see a difference there are filters available for filtering out IR. The only problem is that they're usually for SLRs, not average consumer cameras.

Answer 2

if the sensor is sensitive to IR and it isn't blocked the exposure of the rest of the spectrum will be effected as it is if you take a picture with a snow or beach background.

If the sensor is not very sensitive to IR then there is no need to block it.