Canon Pellix

The Topcon RE Super has its meter cell placed directly behind the reflex mirror into which a pattern of slits are cut to let the light though, while the Asahi Pentax Spotmatic has a pair of cells located on either side of the finder window, reading light off the focusing screen.

Improvements included the addition of a quick film-loading mechanism and contacts in the base of the battery compartment for a separately available electronic booster for the internal exposure meter.

[3] The semitransparent fixed mirror in the Pellix, for the first time successfully used in a 35mm SLR camera, lets about two-thirds (66%) of the light from the lens pass directly through to the film, while the rest is reflected to the viewfinder.

[1] This arrangement supports TTL metering, provides simpler construction and quieter operation, and does not black out the viewfinder during exposure.

Another risk is light reaching the film through the finder window during exposure as there is no raised mirror to block it.

This is avoided by a finder blind operated by turning the ring under the rewind knob, especially useful when leaving the camera on a stand.