Canon EOS 600 - Manual (Page 89)

Ten eyesight correction
powers of +3, +2, +1.5,
lenses are available in
+ 1, +0 5,0,-0,5,-2,-3
and -4 diopters They make viewing and focusing
easier if you are near or far-sighted
• The dioptric adjustment lens consists of a
correction lens and removable rubber frame
(eyecup)