David Dyer-Bennet wrote:

The F at least was 1/60, which was the common standard on all the
horizontal cloth-curtain bodies I've owned (Miranda Sensorex, Leica M3,
Pentax Spotmatic) and many I've read up on or examined.

On pre-Spotmatic Pentaxes such as my S3, the X speed is in between
the 30 and 60. On my Praktica F.X3 (around 1958), the X speed
looks to be just a little under 1/50 second. (much closer the 50 than
25 on a rotating shutter speed dial)t

Peter.
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