Calibrating focus – lens with bolts on focus ring

[yukosteel]

There is large number of recently developed inexpensive manual focus lens from Chinese brands.

It often happens that focus is not perfectly tuned for infinity, but fortunately many of that lens can be calibrated without disassembly.
If focus ring has bolts on it - most likely such lens focus can be calibrating that way.

The detailed guide:
Calibrating focus – lens with bolts on focus ring



[/url]

[marcusBMG]

Thanks for that. The principle is also the same for a number of vintage lenses eg soligor (tokina) 400mm f6.3's.