In my experience, many of the early (dark grey plastic) FA lenses had
what I called a floating front group of elements, and they DID wiggle
around when touched. It should not affect AF, or manual focus, for
that matter, as focus is focus. However, I also found that when using
a polarizing filter, you had to adjust the filter first, then focus.
From a mechanical point of view, I would surmise (might be wrong)
that the moment of movement of that front element/group would be
designed to wiggle around the circumference of the optical (or
physical) curve of the element/group, so that focus did not change.
Pretty far out, huh?
Nothing wrong with your lens... It's an Asahi special design
feature! :-)
On Nov 13, 2008, at 13:05 , John Sessoms wrote:
I'm becoming quite dissatisfied with my FAJ 18-35. The build quality
just doesn't seem solid. When I use a polarizer, the front barrel
slops around as I'm turning the filter, and it goes out of focus. It
feels very mushy.
Has anyone experience with the Sigma 17-35mm f2.8-4 DG EX Aspherical
zoom? Specifically the later DG EX w/77mm filter ring, NOT the
earlier EX w/82mm filter ring.
I'm not really interested in Pentax's new DA lenses because I do
still shoot film, and I want something that will work with my PZ-1P
as well as my DSLRs. The FAJ 18-35 does that, but I'm considering
the Sigma as a replacement due to the poor build quality of the
Pentax lens.
The reviews I've read seem to indicate this is a solidly built lens,
but I'd like to know anything the group might relate from experience
using it.
Joseph McAllister
Pentaxian
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