Still cams and lenses

[becausehowcome 0]

I've done a search with no solid results, I need to know what the differences are between varifocal auto iris lenses and mount lenses. I need a still cam in a retail store. Cam would be positioned on a wall about 12 feet off the ground.

[VST_Man 1]

go with a sony lense, dome or bullet, high res, varifocal. lots out there so shop til you drop.

[jisaac 0]

depends on the application. A.I. is great ( most of the time )

[CCTV_Guy 0]

because ....

 

The names of the devices, varifocal and auto-iris, are highly suggestive of the function they perform. The varifocal lens allows one to vary the focal length of the lens within design limits. One may (manually!) zoom all the way out to get wide coverage area in front of the camera, or zoom in to focus on one particular counter or shelf.

 

Similarly, auto-iris implies an automatic iris .... the aperture which lets in light is enlarged or reduced automatically in order to match the changing ambient light level, resulting (hopefully) in an ideal image under most lighting conditions.

 

In the case of the lens, the alternative to varifocal (which I think one generally pays a bit more for) is a fixed focal-length lens. It's less expensive, but it provides only a single focal length, thus, it's not easily ported to another application.

 

You can determine the focal length you need for your application on any one of a million lens calculators on the 'Net (Googling on "lens calculator" oughtta return a million hits); ours is found at http://www.thermosight.com/LensCalculations.htm.

 

A caveat regarding lens calculators .... in many cases, the algorithm is predicated on industry-standard imaging chip dimensions, but some imagers deviate slightly from that standard. Consequently, most calculators' results are approximate, take'em with a grain of salt. Don't expect accuracy to the n'th decimal place.

 

As VST_Man said, there are a million great lens manufacturers out there and Sony's certainly one of'em. Before you go shopping, however, determine what type mount your camera uses, C or CS, then make certain the lens you purchase matches or can be adapted to the mount you have.

 

Best wishes,

 

bill

[spytown 0]

you mat want to consider thsi camera from Everfocus

http://everfocus.com/Products/PDF%20Data%20Sheets/Cameras/Color%20Cameras/ED300/ED300.pdf

it is high res, comes with a built in a/i varifocal, BLC, AGC and lots of other nice features. For the price, you just cant beat it.

[qman 0]

Neverfocus?

 

that's what rory calls it.

[spytown 0]

i've heard that term before...used to be true...they have come a long way, especially with their new 350 and 550 series