Canon EF - Manual (Page 86)

P Taking a Stopped-Down Meter
Reading
When Canon FL or manual lenses and most
accessories, such as a belows unit, extension tubes,
or a microscope adapter, are used on the EF, it is
necessary to take a stopped-down meter reading.
Stopping-down the lens is done in exactly the same
manner as previewing depth-of-field described in the
preceding section. While the lens is stopped-down,
adjust the aperture ring and/or shutter speed dial
until the meter needle inside the viewfinder is
aligned with the stopped-down metering index mark.
Release the multi-purpose lever and press the
shutter button to take a perfectly exposed photo­
graph.
• During stopped-down metering at small apertures,
it is very difficult to focus properly, because
depth-of-field is very deep, and the viewfinder screen
is dark. Therefore, focus first before taking a
stopped-down reading.
• The multi-purpose lever may be locked into its
stopped-down position. Move the L-M lock lever to
the red "L" position. Then push the multi-purpose
lever in toward the lens.