shauns@tekcad.UUCP (08/08/83)
I've been staring at various cameras lately in preparation for a
purchase (natch). Lately my attentions have been focused on the Pentax
Super Program and the new KA mount. Every manufacturer has a different means
of getting the shutter-speed preferred or full program mode, but it seems to me
that Pentax's is more restrictive than some, to wit:
If you check out the test report in the July Pop Photo, the function of each
pin on the KA mount is called out- one common pin, 2 for minimum aperture, and
3 for maximum aperture. The maximum aperture coding is the thing of interest
here.
Secondly, notice the maximum aperture ratings of the new KA series zooms-they
DO NOT change with focal length. This appears to be required by the KA max
aperture coding scheme, which allows only one maximum aperture in automatic
mode.
This makes life difficult for independent brand lens manufacturers (e.g.,
Tokina, Kiron) who reduce the bulk of their lenses by changing the max aperture
with focal length. I called Tokina on this, and they aren't sure whether or
not they will make a KA mount-it would involve either a total redesign of the
lens (no way) or some electrical switching of the shorting dots on the
lens with focal length, which sounds rather inelegant. Most likely, they will
simply continue making the K mount only (which reduces the Super Program to an
Aperture-priority automatic. Important? Probably not.).
Pentax has come out with some popular range zooms (24-50,35-105,28-135) but all
have a weight and bulk penalty over the independents because of their fixed
maximum aperture.
Consider this if you're thinking about a full program camera and want maximum
choice of lenses.
--
Shaun Simpkins
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