The Project
Those of us wishing to create stereoscopic images using sequential shots
will realise the advantages of using a slidebar. These tend to cost
around £65 and in most cases that I know, are limited to approximately 3"
(75mm) separation.
My
slidebar
Figure 1.
is constructed from a computer keyboard shelf-runner,
available in pairs from B&Q Warehouse in various styles costing between £8
and £12 for the pair. I chose a heavy duty one because I intended to
use it with a rather heavy Canon 10D camera. Slimmer designs are
available if you only intend to use the slidebar with compact cameras.
These shelf-runners consist of two main parts, a traversing member (normally
fitted to the shelf) and a fixed member (normally fitted to the desk)
Figure 3.
The traversing member will carry our camera and the fixed member will be
secured to a monopod, tripod
Figure 2.a
pistol grip or a "bean bag" ("The Pod" in Jessops language), depending on
your requirements. These two members are intersected by a ball track
which make for a smooth, quick action between shots.
I
chose to fit Cullmann quick-release mounts for both camera and tripod, this
is my favourite quick-release device and one that I use for all my camera
mounting requirements (including a bean bag).
My
slidebar is also fitted with a bubble glass level, also available from B&Q
and self-adhesive rubber feet, again from B&Q. The latter are attached
to the shelf mounting lugs on the traversing member
Figure 2. for
ease of operation.
The telescopic action of the shelf runner allows the overall length of the
slidebar is kept to a minimum. In my case, I cut the shelf-runner to
make a slidebar that has a length of 9" (230mm) when not extended; this is
the central position for the camera. This extends to 13" (330mm) when
sliding the traversing member
Figure 3. either
way from centre - providing a maximum image separation of 8" (205mm) for
hyper stereo shots. A unit built for 3" (75mm) separation could be
built to a shorter length of around 6" (150mm).
The trickiest part of the construction is removing the ball-track to allow
drilling and fitting of the Cullmann parts. The balls will fall away
from the track and hopefully into that receptacle that you placed there for
this reason!!. It's a good idea to use grease as a means of holding
the balls in place when re-assembling.
Another point to remember is that in cutting the shelf-runner to the
required length, we will have removed the end buffers. These need to
replaced by a similar device to prevent the whole thing falling apart in
use. I drilled holes in each end of the fixed member to receive a
screw and nut which in turn retained a rubber grommet - this interacts with
the ball-track and can be seen at the centre of
Figure 3.
Cullmann quick-release mounts are available at around £15 from Jessops
www.jessops.com who also have
their own, cheaper "universal quick release adaptor" at around £8.50.
7dayshop www.7dayshop.com
sell a similar device by
Hama
"The
Pod" is a good idea for any type of photography and costs around £15
from Jessops - or even less from 7dayshop
