P3D RBT X4 - problem understood and nearly solved

["Alan Mahon" <alanmahon@xxxxxxxx>]

George Themelis said:-

>The final issue is this:  Does the uneven spacing make any difference?  Is
>this a problem for any one?

>Even if the spacing is uneven between some frames, the complete sequence is
>consistent as film advance is based on sprockets and it follows the 8 and
>24 perforation sequence.  If the lab's equipment are cutting and printing
>based on perforations, they should not have any problem.  Alan has reported
>problems.  Others do not report problems.

You are almost there George, keep thinking and sharpen the pencil just one
more time.  The spacing IS a problem.  Labs cutting and mounting slide film
will damage half the images.  They line up the first image then cut every 8
perforations blindly.  The first two images will be fine the next two will
be cut in the wrong place and then the pattern repeats.  Even if I have to
cut the film myself with accurate spacing I could use my film cutter to give
me film chips good enough for mounting in 2x2 mounts and viewing in a hand
viewer.  Superior images would be moved on into RBT mounts.
Negative film is probably not used too often in RBT cameras but having
discussed it with a minilab processor he is unhappy with my films.  Their
automatic equipment looks for the dark 2mm gap as the identifier of the next
image to be printed.  Fortunately if I'm prepared to wait a couple of weeks
for results I can send negative film from ANY camera, 4 perf, 5 perf 7 perf
(or from home made cameras such as my 68mm stereo base disposable made from
two 3D Magic cameras - the camera Image Tech should have made) to a member
of the UK Stereoscopic Society who runs a minilab and will manually deal
with films for members at normal charges.
The even spacing I crave is therefore an advantage and certainly no
disadvantage to those who accept the present situation.
RBT may change in the future but what about all the existing cameras?  If I
could engage the services of a brain surgeon I would commission him to open
out the outer edges of the apertures or film gates by 1mm and block off the
inner edges by a similar amount and guess what that would give me (as well
as even spacing)?  A STEREO WINDOW.  It needs to be a brain surgeon because
the surgery would be within a whisker of the vertically running focal plane
shutter.  Any volunteers?