Re: vivitar 35-85mm vs pentax 24-90mm

[Fred]

> BTW I am thinking of using it on a mz-s but it has large structure
> around the apeture ring anyone got rid of that before

Unfortunately, the "original" line (mid-1970'2) of VS1 lenses had a
"generous" amount of baffling at the mount end, which causes
problems with some K-mount bodies (and I think that the LX is the
oldest body that is not happy with the extra flange these old lenses
have).  Here are some image links illustrating the removal of this
flange:

First, here are two VS1 35-85/2.8's, the left one of which shows the
extra baffle, while the right one has been modified -
<http://www.cetussoft.com/pentax/v358528/1ofeach.jpg";> .

Lacking access to a bench grinder, I resort to simply cutting of the
excess baffle material with a hacksaw (but leaving the protective
"hump" near the coupling lever, as in jen-you-wine Pentax K-mounts).
(Another PDML-er reported using a thin file for this procedure.)  I
don't try to remove the baffle entirely, but I leave about a mm or
two of it still sticking out (since trying to remove all of it would
tend to scar up the face of the K-mount flange, and removing it
entirely is not really necessary, anyway).  I then smooth off the
remaining edge of the baffle with a fine-toothed file and finally I
touch up the exposed (shiny) metal edge of the remaining baffle area
with a black "magic marker" (for a little flare prevention).

It is important, of course, to mask off completely the rest of the
lens when the extra baffle is being removed from the lens (since you
don't want any little aluminum filings "adding" to the lens' innards
- <g>) - <http://www.cetussoft.com/pentax/v358528/lensmod.jpg";> .

It is also possible to ~carefully~ remove the K-mount flange from
the lens and then remove the extra baffle after masking off only the
flange - <http://www.cetussoft.com/pentax/v358528/flangmod.jpg";> .

I've used lenses that still had the extra baffle protrusion on the
KX, the ME Super, and the Super Program, but I've found that the
flange does come quite close to impacting the upper mirror box
baffle in the LX (when first inserting the lens mount into the body,
before twisting/locking it into position), so I've routinely
performed this "surgery" on some of the "original" VS1 lenses (and,
believe me, it is indeed worth the trouble for some of 'em - <g>).
I suspect that this procedure would be necessary to use any of these
ol' classics on most (if not all) of the newer autofocus bodies.

Fred