Kinoptik 9mm 1.5 921 Filter Thread Size/Pitch?

[Robbie Haltiner]

Hello,

I have recently purchased a Kinoptik 9mm 1.5 921 in Arri B mount and I have had no luck figuring out the exact filter thread specs of this lens. Measuring with callipers it seems to be about 45 or 46mm in diameter but every step up ring I have tried (without forcing it) seems to be the wrong fit.

I am beginning to wonder if this lens has a different filter thread pitch than most? I have scoured the internet for answers so asking here as a last resort. Any info anyone might have would be greatly appreciated 🙂

Thank you!

[Dom Jaeger]

Is the front thread for a filter, or is it the thread for the front optic retaining ring?

Not every lens has a filter thread.

[Robbie Haltiner]

Thanks for your response, Dom.

I am unsure about this - if it were a thread for an optic retaining ring would it still accept a screw on lens cap? The lens did come with a cap and it screws in perfectly.

Robbie

[Dom Jaeger]

It might take a screw-in cap, but not necessarily be a standard filter thread size.

If you have calipers and a thread pitch gauge you can measure the cap thread (rather than the lens thread). Usually the thread will measure a few tenths of a mm under the nominal size. Or take it to a shop that has those tools - a fastener supplier or lens repairer for instance.  

[Robbie Haltiner]

Thank you very much, Dom.

Measuring the cap itself is a great call, I'll give it a shot!