But, many macro lenses focus partly by zooming to a shorter

FL...

On Fri, 24 Jan 2003 05:25:42 GMT, "Reefpup" <reefpup@adelphia.net> wrote:

>So based up on that I get the following:

>

>5T - ~90mm

>6T - ~80mm

>5T + 6T - ~72mm

>

>Thanks, that helps. I think I might be better off just getting a true macro

>lens.

>"Rudy Garcia" <rudyg@jps.net.invalid> wrote in message

>

>> The effective focal length of a lens and a diopter is fairly easy to

>> calculate. Just add the diopter values of the 5T and the zoom at the

>> desired focal length and then convert back to focal length. The

>> conversion is:

>> 1 diopter = 1/ focal length in meters