Re: Homemade macro camera?

[P3D John W Roberts <roberts@xxxxxxxxxxxxxxxxx>]

>Date: Fri, 31 May 1996 17:35:21 -0500
>From: P3D Greg Erker <erker@xxxxxxxxxxxxxx>
>Subject: Homemade macro camera?

>George wrote:

>>There are two basic stereo microscope designs:
>>
>>1. Greenough
>>2. Common main objective (CMO)

>  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 :)

My visualization (as of 3AM on a Friday night :-) is that installing a
divider won't change the optical paths, though it will block some of the
light. Instead of two small images (left and right view), you'll end up with
a full-size but dark image, with a black line through the middle.

Mrs. Whitehouse used to take two lenses and grind away one side of each
(but not all the way to the center - when looking at a lens from along its
axis, picture it not as a circle but as a "D" shape), then cement the two
partial lenses together side by side along the ground edges, and mount this
assembly in a camera with a divider as you describe. This allowed her to take
close-up stereo pictures with an interocular less than the diameter of the
lenses (many of these pictures were of bird nests). Since the system really
uses two lenses for the left and right views, keystoning is not an issue.
The effective interocular is the distance between the centers (optical axes)
of the two lenses.

A few years ago, I tried to come up with a way to do this for SLRs, possibly
by modifying close-up lenses. I put it off as being too time-consuming,
but that doesn't mean it can't be done. If you get something working, I'd
appreciate hearing about it.

John R


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