1
\$\begingroup\$

This is the photo of the lens mount of an F-mount Tokina 10-17 mm (taken from online). What is the lever that I marked in red for? Note that this is not the aperture lever (which you can also see on the bottom right).

enter image description here

Improve this question
\$\endgroup\$
1

1 Answer 1

Reset to default
5
\$\begingroup\$

The extra lever is the "Maximum Aperture Indexing Lever" or "Lens Speed Indexing Lever". It was added on some AI-S lenses to transmit the maximum aperture information to the camera body.

It was only used on FA & F4 camera bodies for more accurate automatic multi-pattern metering.

Improve this answer
\$\endgroup\$
1
  • 1
    \$\begingroup\$ ...and Tokina appears to have chosen to use a metal tab on their F mounts that can be adjusted to suit different lenses in their lineup, rather than die casting a different rigid mount for each lens type. An economical design decision. \$\endgroup\$
    – HamishKL
    Commented Feb 24, 2016 at 23:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.