Gideon wrote : Thanks for the info. However do you have the specs for the
amount of material to
> be removed and to be added in the strip?
>
Hi Gideon,
You need to remove about 1.5mm to 2mm of metal from the rim of the aperature
ring. The finished rim should not touch the camera's coupling catch when the
lens is mounted on an AI camera. You could either file 2mm off the entire
rim, or just around the part where the camera's coupling catch is. I decided
to file 2mm off the entire rim, as it looked nicer. If you have an AI lens,
then use it as a reference to gage how much to file off. I recommend you use
a rough file to start with, and then use a fine file to finish off.
The strip looks like this :
_______________
[ ______o____o_]
[_] <-- lens's coupling catch
I used a small piece of stainless steel to make the strip, but aluminium is
easier to work with. The two holes should be the same as for the prong.
In general, the higher the minimum f-stop number, the longer the strip needs
to be. For my Soligor 135/f2.0, the strip was about 15mm long. The best way
to determine the length of the strip is by measuring the location of the
coupling catch from a lens with the same aperature which you want to modify.
However, unless you do a really good job, modifying your lenses would
devalue them. I recommend you to hunt around to see any repair shop has the
Nikon AI aperature rings you need.
Hope this helps,
Sover
ps I live in Switzerland, a land overflowing with milk and honey
