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 Post subject: noob question - camera distance
PostPosted: Thu Dec 25, 2008 12:57 pm 

Joined: Oct 2005
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Hi im a bit of a newb. My first cctv camera was a cheap ebay day night one and the picture was very close. How can I explain like nearer to you which was great.

I then bought a more expensive camera as I started building up my setup. The picture was great but was further away, ie camera mounted in same location but the actual picture was further out.

If I say was focusing on my car the first camera would give me a nice shot all around the car but then my new camera would be zoomed right up to the windscreen.

When choosing a camera what specs should I be looking at to find out how far in/out the picture will be.

Thanks.


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PostPosted: Thu Dec 25, 2008 7:34 pm 
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What you're talking about is "field of view", also sometimes referred to (incorrectly) as "zoom factor". It's a direct function of the focal length of the lens used: the longer the focal length (usually expressed in millimeters), the tighter the field of view will be, and the closer the objects will appear.

For a complex, technical explanation, check here: http://en.wikipedia.org/wiki/Focal_length

There's a simpler guide here, including some examples: http://www.ezcctv.com/cctv-lens-guide.htm

Since you're probably using 1/4" CCD cameras, you'll find the most common lens lengths are 2.8mm, 3.6mm and 8mm. You should be able to obtain different lenses and swap them out in most cameras, but you'll have to focus them yourself, and some cameras will be easier than others to access the lens. Be particularly careful with outdoor cameras that may be weather-sealed - you don't want to damage the seals.

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PostPosted: Fri Dec 26, 2008 7:01 pm 

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Thanks very informative site. I could spend a fortune their, but how do you buy anything theres no prices or shopping cart. Weird :cry:


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PostPosted: Fri Dec 26, 2008 9:49 pm 
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I would imagine you need to register an account first... prices may vary depending on whether you're an end user, reseller, installer, etc.

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Matt Ion, Omnigeek
LPS Loss Prevention Systems - Maple Ridge, BC

Authorized VIGIL Reseller
------------------
(\__/)
(='.'=)This is Bunny. Copy and paste bunny into your
(")_(")signature to help him gain world domination.

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