Thanks for your help. Thanks to the pictures and instructions, I have just ground off the necessary bits of extra flange using a dremmel, and have maintained the condition of my lens. I guess this mod means it's no longer Like New, but fits great on the *ist D now.
IL Bill On Saturday, January 10, 2004, at 03:15 PM, Fred wrote:
Putting together a bag for my ist D (this may be interesting to those with film & vivitar lenses), and was trying out various lenses. Trying to put on my Vivitar Series 1 90-180mm Flat Field, I found the flange at the back of the lens to be too long.
I know someone had cut this flange down, but don't remember who, and don't remember their description/web page on doing it. Can anyone give me a hand here?
I love the ol' VS1 lenses. (And, now with V.1.1 of the *ist-D's firmware out there, they're gonna be used a lot digitally, too.) Here's from a previous post:
A PDMLer wishes to buy my Vivitar 90-180/4.5 Macro Zoom. He wishes to know: Can the 90-180/4.5 be used "safely" on an MZ-S without filing down the lens's unusually long rear extension?
My personal opinion is that the potential problem (of the excess baffle material on the "original" line of K-mount VS1 lenses) is not too difficult to fix (takes perhaps a half hour) and therefore should be considered to be a mandatory routine procedure before using any of these old gems on a newer body.
I once had to have my Super Program's aperture mechanism repaired when the 90-180 got stuck on it. I may have inserted the lens carelessly, the same way I damaged my Rikenon 50/1.4P: by trying to wiggle it onto the body "blind" while the body was mounted on a tripod, too high for me to see the red alignment dot.
I have used several of the first generation VS1 lenses (with their "extra-generous" baffle extension on the K-mount flange) on several different bodies (including a Super Program) without any trouble. The clearance when inserting one of these into an LX, however, is quite small, and I think that any of these lenses should be modified before using on an LX.
As for the newer autofocus bodies, I think that it is simply not worth "playing games" here - the "operation" should be performed without even trying to judge how the lens and body will fit together.
[from another thread] Here are some image links illustrating the removal of this flange:
<http://www.cetussoft.com/pentax/v358528/1ofeach.jpg> .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 -
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).
<http://www.cetussoft.com/pentax/v358528/lensmod.jpg> .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/flangmod.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 -
Fred
