Hektor 5cm f2.5-Screw in filter?

[elmer3.5]

Hi!

I´ve been using this fine lens for a while, have to say i corrected focus shifts but to my surprise it has the same "shift" as a super fast lens like the sonnar!
From f3.2 on back focuses @ full aperture f2.5 focus goes infront!
Anyway i managed to correct it to a acceptable range, about 1 inch front @ f2.5 and from 3.2 on it backfocuses by 2 inches.
In actual shooting it doesn´t matter cos´DOF is larger enough from 10 feet on.

The best pàrt is the lens at f2.5 is quite sharp, flare resistant and collapsed in my m9 makes it so pocketable, my perfect match!

The only problem is i need a filter, i know i can use an A36, but i would like a screw in to change apertures faster.
I think it must be about 20mm thread but does anyone know where to find the perfect filter?

Thanks in advance.

Check this shots! No PP sharpening!

@ f2.5

Subway shot scale focus @ f2.5

@ f4.5, this lens has the old european scale 2.5, 3.2, 4.5, 6.3...

Bye!

 

[elmer3.5]

Thanks! not very pupular lens.

Until i find one exact filter i´ll fix those "magnetic filters" better than having none at all.
I already use one of those on my x1 and it´s very useful!

Thanks again!