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| This image was taken using a pair of Zenitar 16-mm focal length lenses on an RBT X3B stereo camera (full frame 35mm format). This image shows both the benefits and problems when using these short focal length lenses for stereo photography. | |||||||||
| The benefits are the most obvious. It shows quite a panorama even in a tight space. The child on the right edge was "side by side" to the right of me while still showing the room far to the left at the same time! Image is of the IceFire Glass works in Cannon Beach, Oregon where one can watch glass art being made before one's eyes (one usually purchases some of it as well, great work!). | |||||||||
| The most obvious shortcoming of the lens is the barrel distortion that curves the image, most strongly near the edges. This distortion is further reaching than one might think.
There also is a problem when things in the image are too close to the front edge. Although this might be okay for 2D photography, it presents a couple of problems in 3D. One problem is the traditional near/far mounting problems that stereo photography can have, but the other problem is one more specific to this kind of lens. Because the lenses in the camera are 75mm apart (center to center), items close-up to the camera are in different locations in the two images. This causes the barrel distortion of the item to be different between the images! Things further away are closer to the same relative point in the images so that the left and right will be distorted in a more matched fashion. Of course, I could have "fixed" the problem with the near-glassware in the image above by cropping it out of the picture before you even saw it for the first time, however I left the image pretty much as-is (with "mounting" optimized for the glassware being included) just to show off what happens when it's there and to see the full effects of the barrel distortion. This image is from my very first roll of film experimenting with this lens set (and yes, some of the other images were much better but wouldn't show what I wanted to show). Conclusion is that the lenses provide great opportunity, even with 3D photograph but that items close-in provide special problems because of the barrel distortion, and the temptation to use the extreme depth of field that these lenses provide needs to be tempered, at least when that which is close-up is on the edges -- in the center should be better. Or at least better if it can be at the center of both left and right images. |
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| This is another stereo pair (in triplet form) made using the same Zenitar 16mm lenses. The knee-high wall on the left and right sides are 90-degrees apart, with the photo taken from the corner. Without the immediate foreground items in the image, it works a lot better than the first image above, even though the distortion is obvious near the right and left edges. The slides in this image were scanned using an Epson 2450 flatbed scanner. I took this photo at the Chinese garden located in downtown Portland, Oregon. It's supposed to be the largest garden of its type outside of China. | |||||||||
