Posted: Mon Jan 15, 2018 5:48 pm Post subject: |
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DConvert wrote:
tom_m wrote: |
Ah I see, sorry about that. I was describing the lens with m39 - mount. From what I read there was a difference in the mir 1 lenses. But I’m getting conflicting info from various places. I guess I won’t really know until I get the lens (though not sure how I could tell the difference other than seeing how a filter goes on maybe), but the last thing I want to do is cross thread or strip something.
I ended up finding raf. I don’t know if I should buy one now, they seem to only have one in stock. They’re $30. Hate to buy something I don’t need of course.
This was one of the sources of confusion. http://camera-wiki.org/wiki/Mir-1 ... the one I got is an earlier model, though I’m unsure if it’s the same as they talk about because so many variants were made or different factories used from what I can tell. |
That suggests the model 1 has a different pitch to the model 1B, where the standard 49x0.75 is used.
To check the pitch when the lens arrives try a significantly smaller diameter male thread of known pitch (a machine screw will do) against the threads. If the threads consistently interlock the pitch is the same. If the threads get out of step the pitches differ. IMO this works out easier than trying to measure them or count the number of threads in 5mm & then using maths to work out a more accurate distance for one thread. |