Hi Andre the only thing I really miss from the Olympus XA is a filter thread and a universal flash connector. Otherwise it is a really nice and small camera and nearly silent for snapshots. I always have one in the car.
Indeed. This camera offers quite a lot, especialy with the A-16 flash instead of the A-11, but there is no way to use a hood. Filtering is not an issue for me as we now have (or will soon have) ways to filter "after the fact". I heard the XA is very nice for B&W but not up to the best lenses for colour saturation. I don't know if this is true.
I got a Konica C35AF lately for 5$ with 46mm filter thread and a nice 38mm lens and made some good photos with it. You can't set anything, it's fully automatic and the first auto focus model they had in 1977.
Nice small camera. I've never used one. I heard Fujica's similar models, like the GEr, were also very good. Then came AF...
One question regarding old RF and SLR: --------------------------------------
If they use the old 1.3 Volt Mercury 635 batteries, can they just be replaced with 1.4 volt acoustic zinc air batteries or does the camera metering system gets confused from the 0.5 Volt difference, so I would have to adjust ISO settings?
O.5 volt is not a lot. Some cameras can take big differences, depending on internal electrical engineering (Spotmatics for example).
In any circumstances, "acoustic" air zinc buttons are a bargain. When you know you won't use the camera for some time, just tape the vent holes on the battery or it will only last about 2-3 months.
Andre

