P3D Re: Twinned Pentax ZX-M

["Wladyslaw Reksc" <wlad@xxxxxxxxxxxxxxxxxx>]

Title: Re: Twinned Pentax ZX-M

When you get ZX-M (or another camera from that Pentax family)
fortunately you don't need to be an electronics technician.

The remote release terminal on that camera has the following
pin assignment (from the top to bottom): ground, release, preset.
To make sure the synchronization is perfect (if we can call it
that way) first ground is connected to preset (camera electronics
activates and exposure parameters are displayed in the viewfinder).
This is what happens when the shutter release button is pressed
half way. When the button is pressed harder ground signal is
connected to the release pin and both shutters fire. You don't
need to wary about that sequence - cameras will do it for us.
The good news is that when you operate the button on one camera,
those signals are passed via your home made cable to another
camera, so there is no need for any additional external hardware.

I bought the original remote release Pentax cable (used) so it
was cheaper, but I use it only when taking pictures with long
exposure times.

Don't get intimidated by the proprietary shape
of that connector. I went to buy a socked for a standard 14 pin
integrated circuit with gold plated pins (the type with round
opening - they provide the best contact). It costs around $3.
I cut 3 pins out of it (buy the socket that has the middle of
it opened; you may also ask for the same contacts being sold
as just the row of 10 or 20). Then use a file to make the plastic
a bit thinner, so it fits to the camera opening. Before you plug
it in, solder the wires to it. The only problem with that quick
solution is that to disconnect it, you need to pull by the wires.
If you keep both cameras on the bar all the time, you may never need
to remove that connector.

If somebody doubts the cameras fire together after being connected,
I have only one thing to say. If you load both cameras with fresh
batteries and replace them later both at the same time, you shouldn't
have any problems. I tried to experiment with powering both cameras from
one set of batteries and then they started firing on their own at random.
My experience with cameras synchronization is very good. I have taken
several pictures with very fast moving objects (plane rotating propeller
blades, flying birds, water fountains) and to me they were "frozen" on
both slides perfectly at the same time. I'm quite positive that others
should have the same results.

As somebody else mentioned earlier, there
is an issue of cameras shutting off to save the power. I always press the
release button on one camera half way first to read the speeds cameras
select (and to "wake up" both cameras if they were off).

Wlad