Gene F. Rhodes

My current project is reducing the enormous amount of work required to produce orthographic images. By using a super telephoto lens the angles between shots will be less severe so the number of exposures can be reduced as well as the stitching and editing.
The above photo is a 5-exp (Nikon 950) ortho image of my Sigma 70-300mm super macro zoom lens coupled to a Sigma 2X converter and attached to my Pentax ZX-5n. The lens is shown fully extended and includes the extra extension afforded by the macro switch. No converter is designed for this lens, but I am able to use the Sigma by careful handling and by modifying the converter. The lens interferes with a metal lens retainer in the converter when adjusted below 135mm, so I installed a plastic bumper to prevent damage to the lens, but I still have a zoom restriction. Without the converter I can work from 70-300mm, but with the converter I am restricted to 270-600mm, which is ok because 70-600mm is the range I targeted for this project. The second photo is my first successful 1-neg ortho image shot at 600mm. This time I used a tripod and exposed for depth of field. The third photo is also a 600mm 1-neg ortho.

Basic Procedure: The objective is to show only the picture elements directly in front of the camera lens. Only a small strip of each image is used, so many images are required to get complete coverage. Primary shots are of the edges of walls, set backs, driveways, fences, etc. Secondary shots cover the areas between these edges. Nothing is left that shows sides of objects or even hints of vanishing points. Creative editing is required to limit the total number of shots and constitutes nearly all the work required. Telephoto lenses can also reduce the number of images and the editing required. Also see Panorama page.

Orthographic project:: I wanted to create a panorama that shows every detail as if it were directly in front of the camera so that nothing would be lost in perspective. Orthographic projection is a drawing technique that does just this and all lines are true to scale.

This photo is my attempt to create a replica of a wide orthographic landscape, what one might expect from a satellite camera used at a great distance. It is a test photo made from my front yard in Dec 1998. It was shot with a Pentax XZ-5n in vertical format so I could use a 80 mm lens, but exposure details were not recorded . A total of 42 exposures were taken at strategic points to avoid showing perspective, such as edges of houses, cars, porches, driveways etc.

The average was 8 shots per house but more would have reduced editing. I later tried shooting images at 1.5 foot intervals but this proved to be overwhelming, and commercial stitching software was useless for my application.

After scanning, it soon became obvious that a simple stitching procedure would not work. Size relative to image position made it imperative to stitch in zones, such as street objects, at the curb, the house fronts and at the tree line. The curb stitch was almost twice a long as the tree line stitch. This was a surprise but wouldn't have been if I had analyzed the shoot before hand. After zone stitching, the images were resized to fit and then stitched together into a single image. Of course, a great deal of editing was going on at every step.