Re: Fw: [photo-3d] Twinnable SLR's

["Allan Griffin" <agriffin@xxxxxxxxxx>]

Reference David's request:

There are several ways to test for the "out-of-synch"
factor between any two identical SLR cameras. Here is one.
Use your TV set as an oscilloscope.

Put 24 exp.ISO 200 or higher film in your cameras.
Fit them to their bar and set on a tripod 5 feet from the TV
screen.  Focus on screen.  Open diaphragm to max.
aperture.  Set exposure to 1/125 sec..  I recommend that you use the whole
of the films. This should give you at least 10 pairs where you capture the
upper and lower limit of the scans.  The image scans down at approx. 1 inch
per millisecond (ms) on the average large screen and slightly less on
smaller ones. 1ms = 1/1000 sec.  It is not difficult to see and measure the
out-of-synch factor.  Two ms differential is considered the max allowable
for most action stereos and one ms is, of course, even more desirable.  Will
some kind genius confirm the scan coverage in 1/125 sec.?

The reason that you will need to use enough film is that the degree of
out-of-synch varies from exposure to exposure.  You may never get 100% of
pairs within 0-2ms but I figure that if you get 80% or even 70% which are
within that limit, you are in business.  Odd pairs will no doubt be absolute
synch if your max diff. is 2ms.  You will need some clever way of ensuring
that your pairs remain as such and do not get mixed.  Include large rising
numbers in side of frame for positive ID or other.

You will remember that I was recently extolling the merits of taking out
membership in the ISU.  Well, if you do just that and ignore the above
method, you can pay for your ISU membership with the money saved on film and
processing.  With you membership will come copies of the ISU journal
containing, among many other goodies, full details of a great no-cost synch
text which can be used at point of purchase or anywhere.  How's that for a
deal??

Allan Griffin
ISU Secretary


----- Original Message -----
From: David W. Kesner <drdave@xxxxxxxxxx>
To: <photo-3d@xxxxxxxxxxx>
Sent: Wednesday, April 19, 2000 10:44 PM
Subject: Re: Fw: [photo-3d] Twinnable SLR's


> Allan Griffin writes:
>
> > If there is sufficient interest, the above can be explored further.

David Kesner wrote:
>
> It looks like you probably meant for this to go to just Gary,
> but I am interested in how to test Ricohs for synch tolerance
> as I am sure others on this list are - please post here.
>
> That's all for now,
>
> David W. Kesner
> Boise, Idaho, USA
> drdave@xxxxxxxxxx
>
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