----- Original Message ----- From: "Allan Derickson" <alland435@xxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx> Sent: Wednesday, July 21, 2010 3:18 PM Subject: [rollei_list] OT: Stereo Photography
I've thought of trying some stereo photographs with one of my TLRs. Rollei even had an accessory sliding mount for just such a purpose. I think it slid the camera about two and a half inches for the second shot-similiar to the distance between human eyes. You then produce contact prints and obtain or construct one of those old-time handheld viewers. I read somewhere that this will produce a stereo effect when the subjects are relatively close. How would you calculate the necessary lateral movement when the subjects are far away, say like formations in the Grand Canyon taken from the rim?I don't think anyone answered this. The distance between the lenses should always approximate the inter-ocular distance, approximately 65mm. However, at great distances, there is virtually no stereo effect. However, there is nothing wrong with using any arbitrary spacing for an exagerated or enhanced stereo effect. This done commonly in aerial photography where two photographs taken a few seconds apart as the aircraft is moving can be fused into a stereo image. There are viewers made for examining aerial photos consisting of magnifying eyepieces with two mirrors on each side to get the right spacing. Sometimes one finds old aerial survey photos which have inadvertent stereo pairs. I remember looking at some years ago at the UCLA geography department which had the archives of two of the old time aerial survey companies operating in the Los Angeles area (Spence was one and I am drawing a blank on the other). Among the pictures were some of the Twentieth Century-Fox movie lot. I could easily see people in the photos when looked at in stereo. When looking at single images I could tell they were people after seeing the stereo images but would never have known otherwise. Ideally, for stereo the lenses should also face inward slighly just as one's eyes do but I don't know of any stereo cameras which actually do this. The problem with the slider is that one can take only still life with it. The closest two Rollei camras can be placed results in about a four inch spacing between lenses. This would be fine for photographing distant objects where one wanted enhanced stereo. I have seen rigs for using two 35mm cameras oriented vertically, cameras like the Leica thread mount models can be close enough for proper spacing when mounted this way. One of my continuing regrets was not buying a Heidoscope (or maybe it was a Rolleidoscope) I saw at a camera swap meet many years ago. I don't think they wanted much for it then and I could have gotten it. I have rarely seen others and always for high prices.
-- Richard Knoppow Los Angeles, CA, USAdickburk@xxxxxxxxxxxxx
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