Posted: Thu Oct 22, 2020 1:41 am Post subject: |
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Alun Thomas wrote:
The lens looks to be an early Sigma YS mount type, and the particular mount fitted looks to be Pentacon 'Electric' (modified M42). The screw fitting couples the aperture ring to the mount to allow an internal potentiometer in the mount to move accordingly and feed the aperture position back to the camera. It can also double as an aperture control you can easily find with your eye on the viewfinder. |