Electronics > Beginners
Will the attached 100Hz flickering light output cause a problem for CCTV?
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ocset:
Thanks, from these posts it seems that  severe 100hz flickering light, which goes to zero every 10 milliseconds, is certainly not a "definite" for ruining CCTV images.
The Automatic Gain control will take care of it...it seems.
I wonder what the shortest exposure time is for a general CCTV camera?
If its >10ms, then there really is no problem at all.
BradC:
Shortest usable shutter speed is about 1/60th of a second. Longer than that and things start to smear on a budget camera. Quality cameras don't go down that low unless there is no artificial light present.

I have cameras here that will still use 1/1000 at night under streetlight conditions and struggle with strobing on HPS, so an unfiltered led will strobe to shit. Having said that, if the security consultant is any good they'll characterise the light source for both consistency and spectrum to ensure it will work with the specified cameras.

Frankly I hate LEDs in cheap shit light sources, but you can spend money on better lights or spend money on better cameras, more often than not a $4K camera and lens is much cheaper than upgrading the lighting.
janoc:

--- Quote from: BradC on August 29, 2018, 12:32:16 am ---
--- Quote from: janoc on August 28, 2018, 07:24:07 pm ---
Most cameras cannot "disable" the IR filter - that is a physical piece of glass in front of the sensor and most cameras don't have any mechanical means to move it out of the way. In fact, many cheap cameras/lenses have the IR filter even glued on. The "IR vision" with CCTV typically only means increased gain (and noise) and turning on an IR illuminator (a ring or panel of IR LEDs).

--- End quote ---

Even the cheap shit generic Chineseium cameras (Hikvision I'm looking at you) have motorised IR filters and have had for years, so I'd suggest (based on years of experience of actually testing them) that "most cameras have a switchable IR filter".

--- End quote ---

OK, taking back the "most". I am more familiar with industrial and machine vision cameras than specifically surveillance products and there this kind of functionality is not at all common.
ocset:

--- Quote ---Shortest usable shutter speed is about 1/60th of a second.
--- End quote ---
Thanks, thats 16ms approx exposure time.
Do you know what proportion of CCTV camers in use at night (in say city centres) go below 10ms exposure time?
And how many go below 5ms exposure time?
eliocor:
0.0237015%
0.0033377%

 
@CM800: QED !!!  ;)
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