Leica
New old stock. For M39 (39mm screw mount) components like those historically produced by Kalt, the critical specification depends on the lens type you are using. While Kalt is a legacy brand known for various camera accessories, "M39" standardizes the physical dimensions as follows: 1. Flange Focal Distance There are two distinct standards for M39 mounts that determine focus compatibility: Wikipedia Wikipedia +3 Rangefinder (Leica Thread Mount / LTM): 28.8 mm. This is the most common standard for vintage interchangeable lenses.
