When you're not using it, you can just switch the aperture ring off the A setting to save the batteries. I found that one out the hard way
A QL-17 was my intro to rangefinders, a decidedly better way to shoot 35mm for me. I've mostly used a handheld meter, so I've sidestepped the film speed problem. The lens is indeed very good, but I think it's sometimes given more credit than it deserves. I can definitely see a difference when compared to my CV Ultron 35/1.7 for example. All in all though, the camera is very worthwhile and fun!
The photos I posted on the apug convention gallery were all shot with the Canonet G III 17....all hand held and no meter use, see the photo "Fine Wine" it is taken in Bob Carne's Gallery Room of the Elevator Gallery using the room lights and the shots of Les doing his workshop in the darkroom...shot wide open 1/30 hand held...I really like this little camera. It goes with me on the car seat....film was Ilforn XP-2