P3D Re: Stereo Vivid Questions

[Oliver Dean <3d-image@xxxxxxxxxxxxxx>]

Hi, Steve!

Steven Stultz wrote:
> 
> I recently bought a TDC Stereo Vivid  camera, and have a couple of
> questions for anyone who may be familiar with it.  It seems like a very
> rugged camera, I hope that it will perform well. 

It is a very good stereo camera capable of award winning work. Susan
Pinsky, APSA, of Reel 3D Enterprises, used one for years and got many
awards in international stereo competitions from images she took with
it.

> First, it appears to be fixed focus, is that right?  As I adjust the
> aperture dial I see two red pointers on the range-finder dial that seem
> to indicate the depth of field.  Although there is a range-finder knob,
> it doesn't appear to move any lens elements of the taking lenses.

No, this is a fully focusable camera.  The lenses don't move to focus it
-- the film plane moves.  If you open the camera back and watch
carefully, you'll see a very tiny movement of the film plane when you
rotate the focusing knob.  The automatic adjustment of the
depth-of-field scale was a nice feature of this camera.
> 
> Secondly, after consulting the repair manual for this camera, I see that
> although there is no hot shoe on it, there does appear to be a flash
> sync of some sort- the exploded parts view calls it a "flash pin," just
> above and to the left of the left taking lens.  What sort of adapter
> fits it?

The adapter was for a flash made for the camera, and is not standard,
unfortunately.  Others on this list may be able to help you with a way
of converting to a standard PC connector;  at worst, you may have to get
a knowledgeable repair person to install a PC connector for you and,
perhaps, to adjust the synch if it's out of kilter.  

Some of these older cameras came with "M" synch, which connects the
flash circuit 20 milliseconds before the shutter is fully open in order
to accommodate the delay in time for a #5 or #25 flashbulb to reach its
peak brilliance.  "M" synch allows you to synch a #5 or #25 flashbulb at
100th second or less (with a slight adjustment in the f/stop), but won't
work with electronic flash.  

Fortunately, your TDC camera has "X" synch (connects the flash circuit
only when the shutter reaches its fully open position).  Your original
1950's instructions will tell you that for flashbulb photography you
must use a shutter speed of 1/25 second or slower.  At "X" synch, this
slow shutter speed allows enough time, with a bit of margin, for the #25
flashbulb to reach its peak of brightness before the shutter closes.
There was another type of flashbulb, the "SM" or SF", which reached its
peak a lot faster than the #5 or #25, but they weren't as bright, and,
if I remember correctly, they didn't come in a blue version for daylight
balance.  But they could be used with faster shutter speeds at "x" synch
than the #5's or #25's.  

With electronic flash, "X" synch allows you to use the flash at any
shutter speed, because the electronic flash fires with little or no
delay, long before most leaf shutters can close, even at the shortest
speed setting.

> The repair manual doesn't help much on either of these two questions.
> Any advice greatly appreciated.

Reel 3D enterprises (http://www.stereoscopy.com/reel3d/) carries
reprints of instruction manuals for most 1950's stereo cameras.  For
$3.50 plus P&H, the TDC Vivid instructions reprint might be worth your
consideration as an addition to the repair manual, which may not address
operation of the camera as well as the "How to Use Your TDC Stereo Vivid
Camera" instructions.

Cordially,
Oliver Dean