[MF3D.FORUM:1056] Re: Mounting issue

[Brian Reynolds <reynolds@xxxxxxxxx>]

Bill Glickman wrote:
> I need a way to assure my cameras are perfectly square to the stereo
> bar... any suggestions?  I thought of shinning a light through the
> back of the lenses on a wall and measuring their distances, but the
> pattern would open wide quickly...so I could only do it real close
> to the wall?
> 

The easy way to do it is to rest the backs of the cameras against a
railing before taking the picture.  If the cameras aren't lined up
you'll see it and can adjust them.  If you don't think there will be a
railing near by take a ruler with you.

Here is a DIY project.  Is the back edge of your stereo bar flush with
the camera backs?  If so you can make the stereo bar auto aligning.
Buy some right angle stock.  Take the screws off the stereo bar.  Cut
two lengths of angle stock (an inch or two should do) and drill 1/4
inch holes (3/8 inch for European tripod sockets) in one face of each
piece.  You'll have to position the hole so that the inside vertical
surface of the angle stock rests against the back edge of the stereo
bar and the camera.  Put each screw through the hole in a piece of
angle stock and then into the stereo bar.  You may need to get longer
screws from the hardware store.  For American tripod sockets you want
1/4x20 (1/4 inch diameter, 20 threads per inch), for European tripod
sockets you want 3/8x16.  Be careful that you don't use too long a
screw.  If you do you may damage the camera when tighten the screw.
The manual for my Pentax K-1000SE says not use a screw longer than 1/4
inch (from the bottom surface of the camera), so I'd use a screw
length just under 1/4 inch plus the bar thickness plus the angle stock
thickness.  Now the camera back will be aligned with the stereo bar,
and so long as the bar is straight with each other.

> Anyway, I am happy to report that most of my stereo pairs from my
> trip were successfull.  However, in an attempt to not show any black
> shadows, I opened up as much as possible to prevent any shadows...in
> the process, my highlignts occasional were a bit washed out, this of
> course got magnified in the viewer and looked even worse....so the
> leseen learned is never shoot scenes with greater than 3 stops
> exposure lattitude and better to underexpose a tad vs. overexpose a
> tad....
> 

When using slide film you want to do just the opposite of negative
film.  Meter for the highlights and let the shadows fall where they
may.  With B&W film you could adjust the processing to get both
highlight and shadow detail, but that's not really an option with
color film.  The other option is to use graduated neutral density
filters, but I bet that would be a pain with a pair of rangefinders.

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
reynolds@xxxxxxxxx              | "Oooh!"
http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
NAR# 54438                      |       "Dexter's Laboratory"