I have developed three PhotoShop actions to make rectilinear images from the Zenitar 16mm fisheye when used on the ist D/Ds. The actions require Panorama Tools and PTLens, both free downloads. PTLens is a Windows program.
The actions use PTLens to defish the image. PTLens correction for the Zenitar simply chops off the extra image size which converting to rectilinear creates. The first action 'Zenitar Defish' expands the canvas to the correct size to retain the extra image size which is created defishing the Zenitar image. 'Zenitar Spherize' Uses PhotoShop's Spherize tool to squeeze the image back into the original frame size. Works well with distant objects, verticals and horizontals but messes up if there is a diagonal close to the camera. 'Modified Zenitar Spherize' will make some images with close diagonals better. I created a modified PTLens Zenitar lens profile to over correct the fisheye distortion. Compressing the image back to the original frame size with Spherize straitens the diagonals. PTLens must be pre loaded with the correct lens profile before running each actions. This is a pain and I wish there was a way around it. I think the two actions work well but will not give perfectly straight lines in all images. If you have the Zenitar 16mm, an ist D/Ds, PhotoShop and Windows please give these actions a try. Contact me and I will send the actions and instructions. I plan on putting up a web page but I would like to get some feedback first. The actions should also work with the Pentax or Sigma 15mm fisheyes. Powell
