[photo-3d] 3D Camera Synchronisation

["Ray Moxom" <raymoxom@xxxxxxxxxx>]

The item below on 3D Camera Synchronisation is reproduced from the
current issue of '3D Window', the bulletin of the Sydney Stereo Camera
Club. While a small part of the item refers to the work of local club
members, I am more interested in general feedback on the idea of
classifying the various types of twin rig synchronisation. The
original purpose of the item was to make it easier to describe and/or
comment on various synchronisation methods being used.

Ray Moxom

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Types of 3D Camera Synchronisation

To help understand the types of synchronisation used in twin camera 3D
photography, below are defined the various methods used. The 'Type'
number used here is introduced to assist in the understanding of
camera sync. Many stereo workers get excellent sync with the Type 2
and Type 3 methods described below. Camera modifications for 'Type 3
and 'Type 4' sync requires some level of technical skill.

We hope to be in a position to publish a 'how to' article on 'Type 4'
SLR cinching sometime next year.  In the meantime we are sorry but the
club member involved is far to busy to provide help in this area.  His
pair of Ricoh KR-10Ms give absolute perfect sync at a 1/2000th sec, so
the info will be worth waiting for.

Type 0
No Sync - such as when one camera is fired followed by the firing of
the second camera a short time later or when a single camera is used
to take a stereo pair by moving the camera between exposures.

Type 1
Non Coupled Sync - such as two cameras mounted on a bar and fired
together by pushing both buttons at the same time

Type 2
Simple Coupled Sync - such as cameras mechanically coupled with twin
cable releases or via electrical connection between cameras (the Part
1 method of Wlad Reksc's Ricoh 35R series in this issue is one
example).  This method of synchronisation can be variable, however it
can also be highly successful when electrical connected cameras are
well matched as described by Allan Griffin in the many articles he has
published on this topic - particularly his recent series in the ISU's
Stereoscopy. Mechanically coupled cameras using the Alan Chenery
seesaw leaver arrangement described in the Jan 1997 issue of 3D Window
can also be highly successful.

Type 3
Wake Up Sync - such as a 3 or 4 wire electrical connection between
cameras that also couples the 'wake up' signals (eg later parts of
Wlad Reksc's Ricoh 35R series).  This is also the method that Robert
Brand has used successfully to synchronise a number of Ricoh KR-10M
SLRs for SSCC members.

Type 4
Full Sync - such as cameras wired in master slave mode (eg David
Stuckey's Olympus XA twin rig series that commenced in Sep 1999 issue
of '3D Window').  This is a superior, and more complex, method of
making a pair of cameras operate as one.  In the case of the manual
wind Olympus XAs this can be achieved with a 4 wire connection
parallelling the opening and closing shutter solenoids and removing
the battery from the second camera.  However, for motorised SLRs such
as a pair of Ricoh KR-10Ms there is a need for a 6 or 7 wire
connection between cameras, plus modifications at circuit board level.
This type of modification is definitely not for the faint hearted.


 

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