On Mar 1, 9:24 pm, chili-girl wrote:

1 - Is there a typical distance you can read a number plate.
2 - Would I then be able to read a number plape at say 25m.
3 - What would the picture be like at night with IR on, or are they
just too grainy
4 - Or are my problems only due to the PC capture card.

During the day you may get to read a number plate if the vehicle is
moving slowly and it's only a few metres away or you have a very good
telephoto which you can point straight at the front or rear of the
vehicle.. With all the CCTV cameras I've used, about one third of the
plate is blurred over the rest, making it unreadable. At night I once
managed to read a plate, only because the car was almost stopped about
5 metres away.
What I'd like is an infrared flash that flashes 25 times per second
all night, but I've not found one yet. I may try to make one using a
spinning wheel and some infrared LEDs. If the plates are reflective a
few LEDs will reach 6 metres or so.

Look up "trail camera". There are some with an infrared flash that
take a photo when movement is detected.

Otherwise an ordinary digital camera focussed to infinity will take
excellent flash photos up to 50 metres away for a moving vehicle. If
the vehicle is not moving, a three second exposure focussed to
infinity using a tripod will get plate numbers at night without using
the flash.