Our hope is that this article will help answer questions like these and help to understand some of the concepts that surround sensor size, and lens choice.

The short explanation: all 3 of these lens sets are rehoused Canon Rangefinder still photo lenses from the 1960s. These lenses were used with Canon and Leica rangefinder cameras of that era, and typically had LTM mounts (Leica Thread Mount), which is why they are often referred to as Canon LTM lenses.