Re: Vertical misalignment

[P3D <gnored@xxxxxxx>]

Bercowitz says: 

> If you correct for one camera lens being higher than the other by 
> rotating the film chips back to vertical, you will see vertical parallax 
> within the chips.  If you just mount regularly (and for equanimity tilt 
> your head when you view, the way the camera was tilted when you took the 
> picture) you won't have any vertical parallax.
>
>From a pragmatic point of view, I believe this to be true. A few 
weekends ago I noticed an entire field full of Texas Spider Lillies 
(very rare to see more than one or two). I got out to photograph 
them, and found that I had to stand knee deep in a muddy draining 
ditch. Somehow I managed to get the camera off-level, (tripod 
probably sank in the mud) and the only good picture shows a sloped 
horizon line. 

I mounted this picture in an RBT, making no adjustment for the 
horizon. It looks fine (though it looks like someone was standing a 
little crooked).  I can tell that if I want to straighten this 
valuable shot, it will require rotation _and_ vertical adjustment. 
Needless to say, this slide has been on my To-Do list for awhile!

With the beamsplitter I found that things can get misaligned, even 
when the camera is level. The Pentax beam-splitter attaches to a 
free-spinning mounting thingy. It is almost impossible to get the 
beamsplitter and the camera aligned correctly, much less getting both 
parallel to the horizon, particularly when you're hanging by a tree 
on a 65 degree slope, or standing waist deep in icy water! The 
practical upshot of all this is that I spent a _lot_ of time making 
vertical adjustments when I mounted these slides in half-frame RBTs. 

Gary Nored


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