I have fitted an old manual microscope objective mount to my Pentax K-3. It asks for the F-stop to proceed, which the lens cannot provide. I have tried all settings in the camera including manual focus and all options through the menu.

I imagine this problem is common to all older manual lenses.

  • \$\begingroup\$ Could it be that it's not asking for the f-stop (aperture) but for the focal length, in mm? That's only needed for SR (shake reduction), so either turn SR off or just enter any value. \$\endgroup\$ Commented May 11, 2020 at 5:00
  • \$\begingroup\$ Did you set "Using aperture ring" to "Enable"? \$\endgroup\$ Commented May 11, 2020 at 7:39
  • \$\begingroup\$ Here's more. Does your adapter short the electrical contacts (it should according to that post). \$\endgroup\$ Commented May 11, 2020 at 7:52


Your Answer

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

Browse other questions tagged or ask your own question.