Re: Twin Rig Test

[P3D brian whitehead <berger@xxxxxxxxxx>]

Thanks for your interest in my article on twin rigs. This 'Net@ sure
seems a friendly place. In reply to your querys

> What is the custom black box for?  Was it made by Pentax just for the
> purpose of synchronizing two cameras?  Does it contain any electronics or is it just for the electrical connection of the two cables?

Direct coupling of remote release cables for Pentax caused random
shutter firing(continious) on powering up the rig. Pentax UK designed a
small black box(1.25"x1"x.5") to go inline with the release cable,
primarily to eliminate this problem, which it does
It has no effect on the synchronisation of the pair. This is why its
essential to test a number of cameras( as previously mentioned)for the
best sync.  So I assume that the "gubbings" in the box must be the
electronic equivalent of the old "rectifier" to prevent feedback.
Note: Konica FT's wired direct, fired in sync from each camera button
plus remote.
Good News: Thanks to sharing of information and knowledge I now have
obtained spares through Allan Griffin in Australia.

> Does the Pentax have 1/180 manual speed? (usually most cameras go from
> 1/250 to 1/125)  Are you satisfied with 1/180 synch?  How does that compare with the Konicas?  Are the Konicas consistent at the 1/250s?

With the pentax on auto (which I havent used yet) its a stepless shutter
with infinate combinations. With it on manual the speeds go from
bulb,30sec,20 etc to our useable range 1/10, 1/15, 1/20, 1/30, 1/45,
1/60, 1/90, 1/125, 1/180, 1/250, 1/350 up to 1/2000. As it was the best
I could obtain I had to be happy a top sync of 1/180. On tests at a
theme park, the 50MZ froze everything in sync, except one looping and
twisting ride, where out of 6 shots in varying positions, one was very
slighty out of sync( only a fussy old codger like me would have noticed
it) so for most of my purposes, I'm happy.

> It is OK by me...  Do you also use a regular stereo camera (lens >spacing closer human eye spacing) for subject closer than 10 feet or >for more natural depth impression?
I do not have a "Real" 3D Camera and YOU have found my achilles heel. If
I want portraits or close subjects, I use 135mm tele with a 6" base at
12ft(portraits) with a shallow depth of field from subject to background
or static subject use sequentials from macro, up to my 10ft nearpoint
rule.
Yes its a problem, but Iam happy with my set up, its so adaptable and
variable. I leave close up pairs to folks who have Realists and the
like, they do a grand job in this field. 

> Do you have a way to prevent it from slipping off this setting? 
I can safely set manually the distance of 25ft with my Konicas the
friction on the barrel rings holds firm whilst shooting, however with
the Pentax this is missing and a slight brush with a "coat sleeve" can
throw the focus out, so with a small piece over the autofocus/ manual
switch , I use the same low tech tape to fix focus the lens barrel. No
problem and its easily removed for closer work sequentally.

> I am still using my Minoltas X-700 as my main twin SLR rig.  With 45/2
> lenses it is lightweight and it is still easy to find used bodies and lenses
> in the USA at reasonable prices.  I do not use winders with the cameras and
> do not find manual advance to be a problem.  I have also acquired (and used
> once) a Konica FT1 rig that comes with nice custom-made (just for the FT1)
> bars, including a nice vertical bar (bottom to bottom orientation) with
> convergence control.

Forgot to mention the lightness of the cameras. You are indeed fortunate
to have  a source of X-700 available to you and you are in the right its
not imperitive for motor drive, its just that I was into a fast sequence
shooting of display aircraft, so I plumbed for motor wind on. I note
that you have a twin rig FT1's include " proper" coupling bars, unless
this was a very recent acquisition, I find it hard to believe that you
have only used its once. My 2 pairs of Konicas are just about worn out
with use. Nice to hear from you, just keep shouting and showing and
sharing STEREO.
ITS TOO GOOD A THING TO KEEP TO OURSELVES, CONVERT THE WORLD

Bernard Brown
FRPS  APAGB AWPF
Barry Wales


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