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aperture blade for Biotar 75/1.5 Exa - Fat
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PostPosted: Sat May 12, 2018 11:46 am    Post subject: aperture blade for Biotar 75/1.5 Exa - Fat Reply with quote

Help ...!

where i can buy aperture blade for biotar 75/1.5 Exa - Fat

Broken Aperture

Thank you
Thank You Dog

PostPosted: Wed May 16, 2018 10:02 am    Post subject: Reply with quote


PostPosted: Thu May 17, 2018 12:37 am    Post subject: Reply with quote

I sincerely wish you the best of luck with that. Far too few of those gems out in the world as it is.

PostPosted: Thu May 17, 2018 5:44 am    Post subject: Reply with quote

Tough problem.
The only source of ready-made parts for these would be other 75mm Fat Biotar lenses, such as a broken, parts copy.
But those would be rare.

The only alternative would be to make one yourself, using the other blades as a pattern. I have run across cases posted on the internet of people who have made replacement aperture and shutter blades out of various materials, one being steel shim stock.

I don't think you need to use spring steel like the originals (spring steel will last longer though) but the thickness will need to be identical or very close.

The pins can be cut from a proper guage of brass wire, and held in the blade by peening (flattening with a little hammer) as the originals were.

This would all require a bit of ability as a craftsman. Lots of filing and fitting.

PostPosted: Mon May 21, 2018 10:13 am    Post subject: Reply with quote

This was posted in other thread but i think it is your best bet using such or similar already made aperture and integrate it in the lens: https://www.ebay.com/itm/IRIS-DIAPHRAGM-Aperture-blade-with-M42-x1mm-thread-casing/263262144006

Alternative would be to find similar diameter cheap zoom lens and harvest complete aperture system. Much easier to improvise aperture lens connection then to make blades.

PostPosted: Tue May 22, 2018 2:51 am    Post subject: Reply with quote

Post a picture of the blade on a ruler or pin to pin measurements , then anyone that's working on a lens can compare the blades in their lens to yours.
You may find a blade with a similar measurement but likely a different shape, more like a ) and less like a 7.
I don't see any reason why changing type wouldn't work.