Lens Designs:


Lenses come in a myriad of designs and configurations, but for the purposes of this discussion I will break them down into three basic categories: Symmetrical, retrofocus and telephoto. These three categories describe the basic configuration of the principal planes that are seen in most SLR lenses. These categories have different meanings for normal and close-up photography.

For normal photography the principal planes mainly determine factors such as: compatibility with the flange focal distance and also compactness of the design. These factors really don't interfere significantly in the actual taking of the picture.

For close-up photography the planes significantly affect the optical function of the lens will determine things like working distance, magnification, action when reversed. They will even have some effect on resolution.