Screwpitches

Screwpitches is a term sometimes used to describe a specific type of photographic lens accessory or a modification applied to lenses. It refers to a mechanism that allows for fine adjustment of focus, often beyond the standard range of a lens's built-in focusing ring. This adjustment can be achieved through a screw-based system that moves the lens elements or the entire lens assembly.

These mechanisms are not standard features on most consumer-grade camera lenses. Instead, they are more commonly found in specialized equipment, such as in certain scientific or industrial imaging applications, or as aftermarket modifications for photographers who require extremely precise focusing capabilities. The term "screwpitch" itself suggests a relationship to the threads of a screw, implying a precise, incremental movement.

In some contexts, screwpitches might be associated with vintage or custom-built lenses where manual control and fine-tuning were paramount. While the exact definition can vary, the core concept revolves around a screw-driven system for achieving exceptionally accurate focus. The benefits of such a system include the ability to overcome limitations in a lens's native focusing mechanism, enabling sharper images in demanding situations. However, the complexity and cost can be significant drawbacks.