Rare lens hood / Lens shade - British meassure about 1 9/16

[Mytoy]

Today a lens shade arrived, which was named 39mm and I hoped to use it for My Leica Summitar.
But no way.

It turned out to be non metrical. The Thread has a diameter of about 1 9/16 inches (about 39.15mm) and
a pitch of 24G3/16. It is made of alloy with a depth of 1 inches over all (31mm) and the outside font ha a
diameter of 61.5mm.

Who knows what lenses or manufacturer that shade had been used for?

[DigiChromeEd]

[scsambrook]

It looks like a typical 1950s aluminium lens hood. They were made in just about every size you can imagine at a time when there was really no standardisation of thread sizes on lenses.

I may be wrong thinking this, but doesn't the 50mm Summitar use a lens hood/filter size which is different to the later 39mm sort found on the 50/2.8 Elmar and Summicron?

[Mytoy]

I may be wrong thinking this, but doesn't the 50mm Summitar use a lens hood/filter size which is different to the later 39mm sort found on the 50/2.8 Elmar and Summicron?
_________________
Stephen

Dear Steven the filtersize of the Leica Summitar is 39mm with a thread/pitch of 0.5mm (no äquivalent BSF)
The later Leica might have already switched to the standardized thread of 0.75mm (no aquivalent BSF) for
filtersizes we use nowdays.

This lens Thread/Pitch is rather rouhg. It is even larger than the Lens Bajonet M39 pitch, what is 1mm per round.

Do you know of any brand of lenses what used non metrical filter sizes? How is it with RTH Rank Taylor Hobson?

[scsambrook]

Hello Mytoy!

I'm no engineer, so have little or no knowledge of thread pitches and designations

However, certainly during the 1950s all British makers of still photo equipment used the same metric filter/lens hood sizes as their European counterparts. Often these were for push-on rather than threaded types.

The Summitar does need a 'different' 39mm filter because the threaded part of the lens mount is right up against the front element rather than on the front of the lens mount. That's what I was thinking of ... 'ordinary' Leica 39mm filters can't reach the thread on the lens. You will need either the special filters or an adapter to allow use of the 'ordinary' ones.

The lens hood for the Summitar is a clamp-on type - not a threaded one. It takes the same hood as the later 50mm Summicron and the M fitting 50mm Elmars. The Chinese 39mm screw-in types won't fit the Summitar. Apologies if you knew about all that - I've only just remembered !