Originally posted by TomB_tx The LX metered off the film, but the Spotmatic, MX, and most other Pentax film cameras had meter cells on the prism that metered off the focusing screen. Some other makes had cells in the body, in the mirror, behind the focusing screen, etc - but metering off the film was rare.
Ditto for the Super Program. Available light photography was metered at the focusing screen (mirror down), only TTL flash photography was metered at the film plane (mirror up). I drilled two small holes in my tiny little Pentax supplied viewfinder blind and sewed it like a button to the inside of the camera strap so it was always handy. I used this religiously whenever I pressed the shutter with my face away from the viewfinder (typically tripod mounted shots).
I was rather perturbed to discover the Pentax did not supply a viewfinder blind with the K-r body - especially since Pentax recommends using one when your face isn't at the optical viewfinder blocking extraneous light. I was also outraged at how much Pentax wanted for their little bit of injection molded plastic and I told them so. Pentax sent me one gratis. It too is now sewed to the inside of my camera strap. You have to remove the K-r's eye cup to mount it, but it is worth the trouble to do so for more accurate metering.