24 Sep
2010
24 Sep
'10
2:58 p.m.
Screw-mount camera lenses. 39mm x 25 tpi. (39mm x 1mm
is a less than
perfect fit.)
I thought Leica thread was 26 tpi, but it's been a long time since I cut
one... I have no idea if the Russian Leica 'copies' were the same or 1mm
pitch.
Pentax/Praktica/Edixa thread is certianly 42mm * 1mm pitch. And C mount
is 32 tpi. I think VP exakta is normally 0.75mm pitch (but very early
ones were 0.5mm). I've not measured the Nercury, Robot or Reflex Korelle
threads (to mention 3 cameras I can see from where I am sitting).
All are fine emough (along with the filters I mentioend in the other
message) that I always start them off by turning them anticlockwise until
I feel the threds engage.
-tony