Realist synchronization

[P3D Dr. George A. Themelis <DrT-3d@xxxxxxxxxxxxxxxx>]

Bob Howard summarizes the two flash-synch systems (X- vs. M-)
My understanding from the discussion:

- X-Synch:  Contact is made the instant the shutter is fully open.
  Electronic flash will work at all speeds for classic stereo cameras.
  For (M) flash bulbs to work properly, the shutter speed must be set 
  to 1/25 or slower.

- M-Synch: Contact is made 1/50 s before the shutter is fully open.
  Electronic flash will not work at any setting.  Flash bulbs will 
  work at any shutter setting.

The difference between electronic flash and flash bulbs is that the
electronic flash delivers all the light output in a very short time,
while the flash bubls need 1/50 sec (20 ms) to deliver peak light
output.
  
Bob says, regarding the Realist:

>If the Realist was X-sync it would have to be used only at 1/25 with 
>flashbulb.
>It was my impression that early stereos were m-sycn only and had to be 
>modified for electronic flash. MY Realist was modified so I don't know 
>if it was once M.

All the Realists that I have tried were working with electronic flash.

The Stereo Realist Manual (1952) says: 

"The built-in flash synchronization
is effective when the shutter speed is set to 1/25 sec.  At this setting
the built-in synchronizing switch makes contact and sets off the flash
at the moment when the shutters are fully open.  If the speed is set
faster than 1/25 sec., the shutters will open and close before the 
flashlamp has discharged all of its rated light output.  This will
make the pictures too blue."

This is a description of X-synch.

Jess Powel ("The Realist, A Repairman's View", 1988) writes:

"(The Realist) will accept electronic flash at any speed!"
He goes on to describe the flash mechanism ("a simple one")
and how to test for proper sychronization.  There is a copper
strip that can be bent to ajust if flash is out of synchronization.

Ed Romney ("Stereo Realist Repair and User's Guide", 1982) writes:

"All Stereo Realist cameras have a special non-standard hot shoe
for x flash synch at all speeds, and bulbs at 1/25 sec."

Dr. T says: "I have not seen any reference that even early
Realists are not X-synch.  Can it be that the legendary Bob
Howard is wrong or that Greg Wageman is sane? ;)"

George Themelis


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End of PHOTO-3D Digest 1367
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