In the auto mode, the lens diaphragm stays open so the meter needle wont move. And the K-mount cams have no mechanism to push the pin of SM lens which causes the lens to stop down. So one has to always use them in manual setting (ie stop down metering). This actually allowed me to buy cheaply lenses with stuck auto-man switch or sticky diaphragm but otherwise good for use on k-mount bodies as these dont matter :)
On Thu, Apr 11, 2002 at 12:41:30AM -0600, William Robb wrote: > > That would explain the several stops discrepancies I got between > metering with a 50mm f/2 bayonet lens and a 55mm f/2 M42 lens, I > guess. > I also discovered that the lens needs to be in the manual > setting to get the meter to deflect at all. > > William Robb > > > > Yes it can! When you put the screwmount adapter on, the > > open aperture sensor on the K1000 body, goes to rest > > on the "WIDE OPEN" position, that is to say the camera > > thinks the lens will operate at zero stops down from the > > current aperture setting. Thus as you stop the lens down > > it gives a true reading as the aperture gets smaller or > > larger. This is the way the original spotmatic meter works > > except it didnt have a aperture cam sensing resistor and > > always assume the f-stop chosen was the fstop for shooting. > - > This message is from the Pentax-Discuss Mail List. To unsubscribe, > go to http://www.pdml.net and follow the directions. Don't forget to > visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
