ture and use of "tilting stages" suitable 
respectively for holding specimens for study 
at each of the scales of interest - micro- 
scopic and macroscopic. By using these til- 
ting stages, it was possible to rotate Speci- 
mens through appropriate angles of rotation 
and thus to simulate the conditions of "con- 
vergent" stereo-photography. 
It is noted here that, while the angular 
fields of the cameras used for studies at 
macroscopic scales were not as narrow as tho- 
se of the camera-microscopes, parallax was 
minimal with parallel-axis stereo-pairs and 
similar recourse was made to convergent 
stereo-pairs. 
Convergent Stereograms 
The equipment and arrangements used for the 
macroscopic scales of study are illustrated 
in Figs 1 and 2. The camera used was a MAMIYA 
Model RB 67 PRO, with a Mamiya Secor lens 
(77544) of nominal focal length 127 mm. The 
film used was PLUS-X PAN (120) with negative 
format of 60 mm x 70 mm. 
The general arrangement is well illustrated 
in Fig 1, showing a "pavement sample" resting 
on the tilting stage, with the camera held by 
its adjustable stand. It may be seen that the 
tilting stage has rotational axes in both 
vertical and horizontal directions. The scale 
of the arrangement may be gauged by the back- 
ground and by the personnel (Messrs Layton 
and Roze of CSIRO) photographed. 
In Fig 2, there is a rather closer view of 
the camera mounted on its stand and of the 
pavement sample and gridplate replica on the 
tilting stage. The control box for the syn- 
chronised flash system may also be seen. The 
gridplate replica was also produced within 
the CSIRO photographic laboratory from the 
original of a glass gridplate supplied with 
the WILD A.10 Autograph used to observe re- 
levant stereo-pairs. 
For the object distance as in this arrange- 
ment, the bellows of the camera were fully 
extended and the principal distance could not 
be known with any certainty. Similarly, the 
object distance could only be assessed appro- 
ximately. The stage was tilted through angles 
of about four degrees in each direction, being 
within the ranges of movement of the conver- 
gent (phi) adjustment in the restitution 
instruments available. In that the axis of 
rotation of the tilting stage lies some dis- 
tance below the "object", there is a small 
element of movement in these stereo-pairs, 
but for practical purposes they may be con- 
sidered as representing a situation of a 
hundred percent overlap. 
  
Fig 1 The general arrangement of the Mamiya 
camera and tilting stage used to photo- 
graph pavement samples for the macro- 
scopic scales of stereopairs 
103 
Fig 2 
Closeup of Mamiya camera arrangement 
and pavement sample standing on grid- 
plate replica on tilting stage