On Tue, 19 Nov 2019 11:27:00 +0000, Martin Brown
wrote:

On 18/11/2019 22:33, T i m wrote:
Hi all,

I was looking into a very basic domestic CCTV solution. I already have
a variety of gear to play with (old cameras, external enclosures,
DVR's etc) but am specifically interested in the very low light
cameras.

Ones using Sony chips tend to have the lowest noise and best performance
in the dark.

I think that's what I have (as mentioned elsewhere) and they did seem
pretty good (to my untrained eye) under pretty low light conditions.
They were quite old so only low(ish?) res at 720 or so?

Cameras intended for industrial machine vision or amateur
astronomy have the ultimate lowest readout noise and dark sensitivity
for a price - however you have to trade number of pixels to get it.

Ah, ok.

I believe some here have mentioned the NiteDevil range but reading
around seems to suggest that these sort of low light cameras (as
opposed to high-end / military I suspect) achieve such with fairly
long shutter times and so are prone to blurring / smearing on any
moving objects?

Starlight is one variety of Sony CCTV camera using the latest generation
chips that will with the right fast lens come close to what you want.
You will end up paying a lot extra for a fast wide angle lens to get the
ultimate in low light video capability. To get an idea of what they can
do have a look at this video:

https://www.youtube.com/watch?v=qlFUaE_e4bo

Interesting.

Skip to the second half for low light video performance of the various
common chips (unless you enjoy mind numbing musak). One trick they often
use is to bin 2x2 or 4x4 pixels to boost signal to noise in low light.

I assume they were all using their own built in IR LEDS and so I would
have like to seen them side by side using a common external IR light
source, so as to get a more accurate comparison of the actual lens /
CCD etc?

This one compares an iphone 6S, camera and two starlight ones followed
by a random promotional video which may or may not be interesting.

https://www.youtube.com/watch?v=cwLsHh2a1VY

Thanks.

If that *is* likely to be an issue, IR would be ok as there is nothing
reflective, as could be basic PIR LED lamps to generally illuminate
the scene.

There are PIR near IR LED illuminators as well as some security LED
lamps that are sufficiently not far IR that I can see them by their
~700nm tail of emission which the eye can see as deep red.

Seen.

I don't have a specific target / scenario in mind, just that the std
IR illumination with colour during the day and b/w at night must be
the norm for good reason?

You can trade signal to noise by averaging over the pixels to get a
better monochrome image instead of a poxy looking noisy colour one. Same
applies to stereo vs mono audio when the signal is marginal.

Interesting.

There are certainly sensors about now when coupled with the right lens
that will give colour video images by the light of the moon. This is one
area where you do get what you pay for

I guessed that might be the case. ;-)

(although overpriced tat exists).

Quite and something I'm keen to avoid and hence why I asked here. ;-)

For food for thought.

Cheers, T i m