Reassembled, Calibrated and Shimmed
Bought a CCTV lens for $30, a 2x extender for $30 CAD and a C-m4/3 mount adapter for $2.
The lens was extremely dusty/oily/dirty and there were metal shavings inside the lens both on the lens elements inside and in the helixes for focus and zoom. Rings did not turn easily.
Disassembled, cleaned, reassembled, calibrated and shimmed this lens.
Purposefully calibrated the focus ring to go beyond infinity so that the back focus could later be shimmed. Allowing infinity focus across the entire zoom range.
Shimmed the lens between the extender and the adapter using simple cotton thread wrapped around the base of the C-mount screw threads.
Pentax 8-48mm f/1.0-1.2, 2x extender and C to m4/3 mount adapter.
Reassembled, Calibrated and Shimmed
Bought a CCTV lens for $30, a 2x extender for $30 CAD and a C-m4/3 mount adapter for $2.
The lens was extremely dusty/oily/dirty and there were metal shavings inside the lens both on the lens elements inside and in the helixes for focus and zoom. Rings did not turn easily.
Disassembled, cleaned, reassembled, calibrated and shimmed this lens.
Purposefully calibrated the focus ring to go beyond infinity so that the back focus could later be shimmed. Allowing infinity focus across the entire zoom range.
Shimmed the lens between the extender and the adapter using simple cotton thread wrapped around the base of the C-mount screw threads.
Pentax 8-48mm f/1.0-1.2, 2x extender and C to m4/3 mount adapter.