Canon FT QL - Aperture; Pre-Setting Aperture and Checking Depth-of-Field

Indest
■ The “X" index is used for synchronizing an electronic
flash unit such as the Canon Speedlite. Although the
shutter speed at “X" is 1/60 sec., it is equivalent to a
very short exposure time during the flash of the flash
unit.
Aperture
Incoming light and depth-of-field are adjusted by turning
the pre set aperture ring to the desired f/stop.
■ As the f/stop value gets larger, the amount of light
reaching the film plane becomes correspondingly less.
For each f/stop up, the light is reduced one-half. Accord¬
ingly, when the aperture is increased by one f/stop, the
exposure is doubled, and when it is increased by two
f/stops the exposure is quadrupled.
■ Certain lenses, however, have no relation to the light¬
ness being halved between the maximum and the next
f/stops on the pre-set aperture ring.
■ The pre-set aperture ring can also be set between two
f/stops.
■ The ratio between the aperture and the amount of
exposure, using f/2 as the basis, is as follows:
f/stop:
1.2 1.4 1.8 2 2.8 3.5 4 5.6 8 11 16 22
Exposure Ratio:
3 2 1.25 1 1/2 1/3 1/4 1/8 1/16 1/32 1/64 1/128
Pre-Setting Aperture and Checking Depth-of-
Field
Lens with A-M Ring
1 Pre-Setting of Aperture: Set the A-M ring at “A".
* Then set the desired f/stop on the pre set aperture^^
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