Welcome to the
All you need to know about lenses,
Selecting the correct CCTV lens for any given application takes a little bit of practice, but as Doktor Jon has mentioned before, there are a few useful pointers which can help to make the task easier.
Firstly, in terms of general performance / flexibility in use, the 1/3 CCD format will provide pretty much almost everything that you need for 90% of applications; and given the enormous range of lenses available, if you cant find one that fits, it's really time to consider a career change!
Wherever possible, if you are selecting a fixed lens, try and use the series designed for the next larger sized imager; so if you have a 1/3 camera, if at all possible stick to 1/2 or even 2/3 format lenses.
Try and remember the lens ratio guide for that format: Ultra Wide = 2:1 Wideangle = 1 :1 Standard = 1 : 2
Yeah, so what does that mean? Okay, well if your camera is pointing at a wall 10 metres away, with the Ultra Wide lens the picture will take in very roughly 20 metres width of wall, with the Wideangle 10 metres, and with the Standard 5 metres ..... and not a lens calculator in sight!
To give you a better idea about the range of lenses available, Doktor Jon has thoughtfully provided a simple comparison chart.
Oh and dont forget, when comparing lenses always make sure that the manufacturers data is indicating the horizontal angle of view, and not the diagonal angle of view.
Too many lenses have been bought and installed, when they are simply not right for the job!!
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