CCTV. What sort of camera is this?

[Simon Cee]

It's the webcam on the beach at South Sands in Devon. During the day it shows average quality pictures, but at night it seems to switch into some sort of infrared mode. I don't mean the scene is lit by infrared light (although sometimes the foreground looks that way), but even in the distance it picks out features in what must be very dark conditions. People walking on the beach show up as bright white - and moored boats in the distance show as grey (warmer than the surrounding water) so it must be detecting heat/infrared. What sort of camera has this facility? I thought this sort of capability only existed within the military.

Link to camera web site;

capture of night shot; cam location - looks NE [45 deg]

50.2251 -3.7843

[alan]

Point your TV remote at your digital camera or phone camera and press a button on the remote. You will see the IR LED on the remote flashing in the cameras viewfinder screen.

The detectors in the camera extend into the near IR and usually have a IR filter to block out much of the IR.

You can convert a normal digital camera for IR use by removing the IR filter and replacing it with a filter that you cannot see through - such as that bit of a developed colour film that wasn't exposed and is still black.

Many surveillance type cameras are designed to operate this way. However the frame rate and/or resolution will be much reduced and the final image may/will be the result of the integration of many frames. You may only see non-moving objects clearly.

Military/Police cameras will operate in a different IR band, at a true

50/60Hz frame rate and will be much more sensitive.

[Graham.]

Most of the digital cameras I own, even the ones in basic mobile phones have a night vision mode which works, I imagine, by ramping up the CCD sensitivity (ISO) and integrating several frames together.

I just took my Blackberry outside (0100hrs) and in the night mode it can easily pick up clouds illuminated by the lights of Manchester.

My son's Canon DSLR can photograph the brighter constellations even without resorting to the highest ISO settings, just because the camera in question is described as a "webcam" it doesn't preclude it having a "fast" lens.

[dennis]

IME most webcams have fast lenses but you can't get stars on them easily. With a point source like stars you need aperture, as much as you can get. A longer slower lens will beat a short fast lens most of the time on stars.

OTOH its quite easy to modify some webcams to take longer exposures and they can fit into telescopes instead of an eyepiece and take good pictures of planets and nebulae.

The webcam in question does appear to be integrating frames when you view it live. Probably about 10 frames looking at it live. I have some and they can make night look like day but moving objects can smear. They are good for detecting motion in dark scenes so you now where to point a better camera.

[Brian Gaff]

Yes, normally one has to cool the elements to below the temp of the lowest possible temp to get it to work I'd have thought.

Brian

[Dave Liquorice]

It may well be doing that but I think its also showing the heat signature of objects rather than reflected visible light. Notice how the underside of the table is brighter than the top, there are "hot" rocks above the "cold" water line on the clifs, the distant boats and bouys show up very clearly.

These sort of cameras don't come cheap but looking at some of the other hotel pages I don't think cost would worry 'em that much.

[fred]

Don't think so, where the deck enters the water you can still see it in the shallows, with long wave IR you would see the temp of the water.

My guess is that this is a sensitive Sony Super HAD based camera (or similar) with auto switch from colour to B/W in low light.