Re: homemade macro

[P3D <PK6811S@xxxxxxxxxxxxxx>]

Greg Erker wrote:

>  This makes me wonder about making a closeup camera with only
>one lens. I have an medium format camera (Ricohflex TLR) with
>an 80 mm lens. Would it be possible to put a divider from just
>behind the lens all the way to the film plane to divide the light into
>left and right halves. After developing cut up the film chips and
>mount them in Realist 5 perf or 7 perf mounts ("Oh no!" exclaims
>orthoman :)

Well... almost!  The left part of the image will be cast by the
left half of the lens, and the right part of the image will be
cast by the right half of the lens, and therefore they will have
been taken from different perspectives.  BUT!  Each will only
be a half-image, not two complete images.  In a simple lens
every point of the lens casts a complete image on the film in the
same place every other point does.  If this were not true all
those non-corresponding images would just be a big blur (which
is what an unfocussed lens is doing, actually).  In a compound
lens the same thing happens.  So you need another way to separate
the image cast by the left half from the image cast by the
right half.

You could maybe introduce a prism in the lens to do this.  Or polarize
the two halves oppositely - then maneuver them somehow to separated
film locations.  Or do what some of us have done which is to 
put red/cyan filters across the diaphram to separate them by color.

I haven't checked this, but it strikes me that some of those special
effects filters which create multiple images must be creating stereo
pairs.

Paul Kline
pk6811s@xxxxxxxxxxxxxx


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