Posted by Dennis Lee on October 14, 2000 at 14:43:46:
In Reply to: polaroid for 6x9 graphic posted by varnell on October 09, 2000 at 06:52:09:
Horseman makes a polaroid back that will fit on the 6x9
graphics. The back
sits a little further back than the normal film plane so the
focus/lensboard
needs to be approriately adjusted. Horseman makes a spacer to do
this and
they also make a special 'polaroid' ground glas that sits back at
the same
distance for accurate polaroid focusing. I have also seen pola 6x9
backs
listed by Arca Swiss, but I have not seen one. Both of these are
fairly
expensive. Usually more than the cost of the 23 camera.
I made my own polaroid back by ripping apart a 6x9 Grafmatic
back and adapting it to an old polaroid
sw-nger back.
Here's the process in a nutshell:
I took the Grafmatic back apart keeping the front of the holder
intact. This
became my mounting plate and slide holder (I'm sure you could also
use a
regular 2x3 film holder for this same purpose, just cut the back
off, and
the inside out. This may even work better for holding the dark
slide). Next
I found a clean old polaroid 'sw-nger' that holds the common
available
polaroid film packs($2). Cut the camera in half using a hacksaw or
jigsaw.
I started somewhere in the middle of the body so I could eyeball
the
connection between my mounting adaptor and the polaroid back,
slowly
fitting/adapting the two together by filing and sawing. Once cut ,
the
plastic back will probably have an irregular and larger hole than
your 2x3
adaptor back, so use a maleable material like cork or balsa to help
seal any
gaps between your plastic polaroid back and the film back adaptor.
I used
cork, which I found in the gargae. I think balsa wood might be a
nice
alternative. Balsa would work better for building the frame to
mount your
adaptor, and also work well to form the frame lines for your
polaroid (ie,
6x9, 6x7...). When
everything is in place make some measurments to make sure you are
still
relatively square between the mounting bracket and polaroid film
plane.
Remember the more accurate you are here the better your polaroids
will be.
Now epoxy it all together to make it rigid and make sure it's light
tight
on the outside. I made mine light tight by rolling up black
velvet
material, sewing it into a rectangular frame and then fitting it
over the
outside of my mounting bracket where it seals to the top of the
polaroid
back. Make this light seal before you epoxy so that you can slide
it over
the mounting bracket after epoxiing. As the epoxy cures it will
seal your
light seal into place between the polaroid body and mounting
bracket
(remeber, the mounting bracket must also hold your dark
slide).
I got the fabric cheap by buying a black velvet skirt
at the local Goodwill, much less than at a fabric store.
Use black cine foil to help make the sharp edged frame lines inside
the
polaroid back and keep down reflections. Machined metal painted
black would
be optimum.
Once the polaroid back is complete, measure the distance between
the
mounting bracket and the polaroid film plane, mark this difference
on the
camera's focusing rails back from your infinity stops (pencil
please). Focus
the camera on the ground glas for accuracy, and without moving the
focusing
adjustment move the lensboard back to the polaroid marks on your
rails and
start making test exposures for focus adjustments. Adjust the
pencil marks
till you get sharp polaroids and then either add another set of
infinity
stops, make yourself a spacer, or just keep using the pencil marks
on the
rails for your polaroids.
I think the black and white polaroid works much better than color
for the
focus adjustment
Also, if you used a polaroid sw-nger back for the project, don't
remove the
strap that comes connected to the back. After your exposure remove
the back
from the camera and pull the polaroid using the sw-nger handle, you
will
never have a poorly pulled polaroid.
A couple evenings in the workshop
and a few bucks will give you a cheap working 6x9 polaroid for your
23 camera.