[MF3D.FORUM:563] Re: exact fl match for paired lenses

[Alan Lewis <3-d@xxxxxxxx>]

This post apparently was lost in transmission:

Bill Glickman wrote:
 The results were poor.  When I
> mounted the chromes I learned why this practice is risky... you can not
> prevent double vision on the side edges.  Although I must admit the center
> looks awesome.  But the whole effect is destroyed by the double vision on
> the edges.    I assume this is simply the consequence of having a base wider
> than it should be..  

Others have guided you in the right direction about setting the window
when mounting.  But let me suggest that you use a standardized mounting
procedure to automatically fix the problem forever (or at least verify
where your problem area is).

First, you should always mount the images with the infinity separation 
at 2.5" apart.  Ignore the mount window at this time.  The viewer you
are using was designed for a 2.5" infinity separation, and if you always
mount to this distance then every slide you view will be focused
properly and be comfortable to view.

Second, while keeping this distance set you can shift the pair in any
direction you want while looking through the mount window (this is where
you use the mount).  This is when you can set the composition for
viewing.  The width of your images will dictate just how much in either
direction you can shift the pair before overlapping the mount window.
Just keep the infinity separation between the images at 2.5".

I believe if you start using this method you will have more comfortable
viewing.  It is possible that if you have an object too close to the
camera for the lens spacing then you will still have a near point window
violation, and this teaches you how to compose your images to eliminate
this.

If you can't shift the images in either direction without overlapping
the window then it may be telling you that your cameras are too far
apart for the image size on the film.

While there are exceptions to this procedure, it will work in the
majority of cases, and will teach you by experience how to set up you
cameras for proper viewing effect.

If you follow this 2.5" separation procedure then you will be able to
determine easily why the image doesn't look right when viewed, and what
you have to do to fix it.


-- 
Alan Lewis  
mailto:3-d@xxxxxxxx
http://members.home.net/3-d
Serious viewers for Serious viewer's
New stereo viewers & Stereo Wedding Photography