DEVICE FOR FOCUSING AN OBJECTIVE

摘要

The lens holder of a lens focussing device is axially movable in a lens sleeve supported on a film holder on which it can slide. The rim of a focussing wheel is accommodated in the space between the collar of the lens and the top face of the lens sleeve. The rim thickness increases uniformly along half its periphery. This results in a relative movement of the lens holder and the lens sleeve when rotating the focussing wheel. The focussing wheel is axially deformable. Notwithstanding the focussing wheel being firmly mounted, this provision allows limited axial movement of the lens sleeve, rendering it possible for the lens sleeve to follow the course of the upper plate of the film holder.