Canon AT 1 - Manual (Page 112)

Data Back A
This is an interchangeable back cover
with a built-in data imprinting mechanism. It
can imprint the day, month and year on the
lower right hand corner of the photograph at
the moment of the shutter's release, as well as
other data to identify or classify the pictures
you take. It imprints letters of the alphabet
and Roman numerals for greater versatility
and convenience.
Canon Bellows FL
This is an adjustable bellows for high-
magnification photography. Magnification is
adjustable within the range of about 0.7 to 3
times the size of the subject when it is used in
combination with a standard lens.
The built-in semi-automatic aperture
mechanism automatically closes the dia­
phragm at the time of shooting and makes the
Bellows FL almost as easy to use as a fully
automatic lens. Focusing is performed with a
bright field of view. It has a built-in strut to
prevent blur. The Slide Duplicator FL for
duplicating slides can be attached to the end
of the Bellows. The use of a macro lens
especially corrected for close-ups is recom­
mended for photography with the bellows.