Re: Recomendations wanted for outdoor video camera (make/model) and retailer

["Doug L" <vssdoug@xxxxxxx>]

A varifocal lens allows you change the focal length between set ranges IE
3.5-8mm or 5-50mm etc, it doesn't hold the focus when adjusting the focal
length. A zoom lens when correctly set up will hold its focus throughout its
entire range.

I don't know about the camera in question but a varifocal lens will have two
adjustment rings, one to adjust the field of view or focal length and the
other to adjust the focus, both will need to be adjusted at the same time,
normally in opposite directions, in order to maintain focus at the desired
focal length. If its a manual varifocal lens then there will be a third ring
to adjust the iris, a bullet or board camera manual varifocal lens probably
won't have an iris adjustment ring.

The varifocal bullet & board cameras that I have seen with varifocal lens
have had these two rings.

Doug L

--

"Video Guy" <Video@xxxxxxx> wrote in message
news:42ECE893.76F6A931@xxxxxxxxxx
>I see that some of these cameras (specifically some of the bullet or
> torpedo type) claim to be "varifocal".
>
> A specific example is the CVC-7706DNV:
>
> http://www.123securityproducts.com/cvhecodaniul.html
>
> Note the link "how to adjust the verifocal lens" :
>
> http://www.resicam.com/techtips/images/7706lens.pdf
>
> It's really a focus adjustment.
>
> I believe a true varifocal lens is a lens that changes it's focus when
> the focal length is changed.  Which means the lens must be some sort
> of zoom lens.  So does the CVC-7706DNV (or any other "varifocal"
> camera) have some sort of external ring or control that allows you to
> change it's focal length (ie zoom in or out) ???