[jawats]

All,

For $20, I picked up a Sigma M42-mount 200mm F/3.5. I have attached a couple photos, from the auction, since I don't have it yet. It seems like a unique and interesting lens. I don't see it here anywhere, and I don't see it at this site Home - M42 Lens Database. However, based on some web searches, it might be a lens called a "Scalematic," from the 1970s.

Does anyone know the purpose of the square near the mount of the lens? I've seen them before, but I've never been sure of their purpose.

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Last edited by jawats; 02-23-2020 at 11:04 AM.

[Lowell Goudge]

This is a baffle to prevent stray light from going into the mirror box

Many k series Pentax lenses have them to

[jawats]

This is a baffle to prevent stray light from going into the mirror box

Many k series Pentax lenses have them to

Thank you!