To be short, I posted this text, associated with the manual Pentax M 135mm/F3.5 lens in the "Lens Database":
Pentax-M 135mm F3.5 Reviews - M Prime Lenses - Pentax Lens Reviews & Lens Database
Important is the extension of the hood, adapted to the new angle of the lens if is transferred from the film camera to the DSLR. This increase the contrast of images if they are shot in contrejour.
Another need for a good manual focus (including the focusing screen, obvious) is a ocular shell to mask the ambient light entering between the eye and the camera improper shell. This parasite light decrease the contrast of the image on the focusing screen, making the manual focus more difficult. See the first image of my camera at the above link.
Last edited by Paunel; 09-28-2011 at 01:03 PM.