Can anyone help me out, I'm currently spec'ing a job for some CCTV cameras for a really paranoid, really rich person. He only wants a 4 camera system but wants as close to 100% coverage as possible.

I stupidly suggested drawing a diagram for him with the positions of the cameras on the house and their approx field's of view so he can see any possible blind spots.

So I need to way to workout with the size & type of lens on the camera what view that camera will have.

Anyone point me in the right direction?


one of the camera's I'm looking at has a 3.6mm lens and the other 2.8-12mm Varifocal Lens.

Cheers
Rob

I only know that a small apature gives better depth of field so I guess the lens which give the best light would be best.

all the cameras I use have 1/3" ccd's if that matters and use the lens I mentioned above. There must be a formula to work out the 'cone' view of the camera.

this is what I want, but with reletively accurate cones.

Think I have found it.

distance x 4.8 / width of view

so if I want to see 18m away and a 21m wide picture I need a 4.1mm lens.

Good job, I've got no idea!  Only lens I've got I know the field of view for is my Sigma 10-20mm which is about 110 degrees but I couldn't tell you how I know that or how to work it out either.

this looks handy

http://www.pelco.com/sites/global/en/sales-and-support/downloads-and-tools/tools/lens-calc.page

I'm guessing you've got drawing software for this, but if not I find QCADs free version works well enough for simple 2D sketches.