P3D Re: Olympus XA cameras

["David Stuckey" <dstuckey@xxxxxxxxxxx>]

Refer to Duane Perry's question in PHOTO-3D digest 3129 about matching
Olympus XA cameras.

There are two issues here regarding the twinning of the XA or the XA2. 
These cameras operate differently.  The XA is an aperture priority camera
whilst the XA2 is a program camera, ie: it is programmed to go for the best
D.O.F. by adjusting both aperture AND shutter speed.  This makes it much
harder to match than the XA because you can get different apertures and
shutter speeds with unmatched cameras.  With the XA, there is a manually
operated detent style aperture selection lever.  The only variable is the
shutter speed.  By coupling the solenoids that control the release of the
shutter and the delay in closing the shutter with timed exposures, one
camera can meter for both shutters.  These solenoids are connected in
parallel with the slave camera being disconnected from its circuit board. 
Batteries are only required in the master camera.  Now the only variable is
internal friction in the shutter mechanisms of both cameras.  Hardly a
problem.

If you only connect the shutter release buttons together, as I suspect most
people are doing, then you have to compensate for the differences in
calibration of the light meters as they are still operating independently. 
This is no doubt controlled by one of the many trim pots on the circuit
board of the camera, but which one?  Also, this needs measuring equipment
and the opening of the case of the camera.  Much better to play with the
ASA setting lever to achieve a closer balance.  Obviously you need to
bracket on a test film to get the closest match.  This method was not
proposed as the complete solution, just a way whereby the average camera
user who doesn't want to try and open up the camera body, can achieve a
close match.  IT WILL NOT WORK FOR THE XA2 MODEL.  I think this is where
the confusion is.

Duane Perry's question obviously refers to the XA2 as he is talking about
different apertures and shutter speeds.  The answer is that adjusting the
ASA setting won't fool the exposure meter of the XA2 because it controls
BOTH functions, aperture and speed.  This is one of the reasons why I
haven't yet attempted to twin the XA2.

Hope this clears up a few matters.

David Stuckey


email:    dstuckey@xxxxxxxxxxx
website:  http://www.acay.com.au/~dstuckey


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