Cannon QL Pre-SetAperture and Checking of Depth-of-Field, Relation Between the Pellicle Mirror, CdS, Diaphragm and Shutter, Lens with A-MRing

èThe aperture ring can also be set to intermediate values.

èDepending on the lens, there are instances where there is no relation to the lightness being halved between the maximum diameter of the aperture and the next aperture reading.

èThe ratio between aperture and the amount of exposure, using F 2 as the basis, is as follows:

Lens Aperture

1.21.4 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-Set Aperture and Checking of 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 ring to the index. The diaphragm will close down to the pre-set F stop only for the instant that the shutter is released. Except for the instant that the shutter is released, the diaphragm will remain fully open.

2.Manually Operated Aperture: When the ~ A-M ring is set at "M" the diaphragm closes down to the pre-set F stop. In this way the depth-of-field at the time of shutter release can be checked. When the A-M ring is reset at "A" the diaphragm again returns to maximum opening.

Lens with Manual Aperture Ring

1.Pre-setting of aperture: Set the desired F stop on the pre-set aperture ring to the index. Then set the index of the manual aperture ring to this pre-set F stop. The diaphragm will close down to the pre-set F stop only for the instant that the shutter is released.

2.Manually Operated Aperture: When the ~ manual aperture ring is turned in the direction of closing down the diaphragm, after

setting the desired F stop on the preset aperture ring to the index, the diaphragm will close down to the pre-set F stop and the depth-of- field can be checked. The manual aperture ring cannot be turned when set at maximum aperture opening.

èRefer to pages 34-35 concerning depth-of-field.

Relation Between the Pellicle Mirror, CdS, Diaphragm and Shutter