Originally posted by steephill 1/15th to 1/3rd of almost a 2 stop range. The LX was a pro standard body and if I remember correctly from reviews at the time had an accurate shutter so clearly was designed to give at least 1/3rd stop accuracy.
Your subject matter has rapidly changing highlights which would make metering very variable. Add in that the LX meters during exposure and you will never get the same result twice. The obvious solution is to use manual mode and set the shutter speed you want.
This is all true. The LX shutter was very accurate for it's day at ±1/3 stop. However, this means as much as 2/3 stop variance FROM SHOT TO SHOT at discreet shutter speeds.
Obviously, they get more accurate as things slow down, below the sync speed, the shutter is probably accurate to within 1/10 stop, for an exposure variance of as much as 1/5 stop from exposure to exposure.
I suspect you have hit the nail on the head with your comment about OTF metering during exposure. There is no practical way of keeping the LX being run in automatic from making fairly wild exposure variances in normal use. If the light change at all, the exposure will be affected.
Note this only happens when speeds fall below sync speed. At sync speed and above, the metering is done off the leading curtain and exposure is locked in at the moment the button is pushed..