2.5.1 Concept
For a few years now, Aaton has inserted a spacer between the lens
port and the camera body. This thin (0.3mm) metallic ring is res-
ponsible for the precise distance between the lens port seat and the
film plane called the flange focal distance (FFD), and therefore it is
also mainly responsible for the sharpness of the images.
In order to change the FFD of the AATON 35-III, simply change
the spacer, and only the spacer. Do not polish any other surface, or
insert anything else between the lens port and the film plane. For
fine adjustment of the FFD, order some aluminium spacers
(0.35mm) from your Aaton agent, and then safely change the FFD
of your camera.
2.5.2 Polishing a Spacer
In order to fine-adjust the thickness of a specific spacer, Aaton car-
ries a specific tool (ref 35 310 32) designed to hold the spacer firmly
and evenly against polishing paper. When polishing a spacer, always
work on a perfectly flat worktable or stone, and be sure to firmly
hold the tool.
2.5.3 Changing the Spacer
The spacer is placed between the PL lens port and the camera body’s
titanium base. First, remove the lens locking ring: screw two or three
turns its stop (placed on the bottom, inside the PL port), and turn
the ring counterclockwise. Remove the PL port by unscrewing its 6
screws. Then gently remove the aluminium spacer .
Once you have placed a new spacer, install the PL port, then the
lenses locking ring, and do not forget to unsrew two or three turns
the locking ring stop.
2.5.4 Adjusting the Viewing Screen
Because you have changed the distance separating the base of the
lens and the camera body, the image on your viewing screen might
now appear to be less sharp than usual. Most likely, you may need
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