The viewfinder magnifier M 1.25x enlarges the viewfinder image by a quarter, making it easier to compose images at focal lengths of 50 mm and above. It significantly improves focusing accuracy, particularly when taking photos with telephoto focal lengths. The viewfinder magnifier is simply screwed into the viewfinder eyepiece of the Leica M and attached to the eyelet of the Leica M carrying strap using a safety chain. This protects it from loss and damage. A leather case is included for storage.

For the Leica M10 it is possible to use the eyepiece thread adapter (24001).