Optics: Very Good/ Excellent for lens’s age. Front element is near mint (very rare) and has a faint blue single coating on it. Some minor cleaning marks and very fine scratch on rear element. Glass has a few micro air bubbles inside (very common due to the glass recipe used by Zeiss during this era). This is a single coated lens, good for both colour and monochrome images, it does not have the T multi-coating, which came a bit later on.
Aperture: Clean and fully working.
Mechanics: A few minor ageing marks, faint scratch on the focus ring between the infinity symbol and the brass focus stick.
About the lens service:
Lens underwent a full restoration and conversion to Leica RF.
All lens mechanics were dismantled and ultrasonically cleaned. Helicoid was re-honed for improved smoothness. Our custom-made brass ‘Air-Feel’ focus stick has been installed on to the focus ring. Helicoid and RF cam have been modified to allow 0.7m ‘Minimum Focus Distance’ while still retaining RF coupling with the camera. Optical elements were cleaned and set to a Effective Focal Length of: 51.6mm, which allows accurate Leica RF focus. Lens has 6-bit coding. The ‘4 and 5.6’ aperture fonts have been painted red, to indicate focus shift apertures. Lens has been calibrated for f/2 (wide open) aperture usage.
About the type of calibration on this lens (potrait optimisation):
This lens has been optimised for wide open f/2 aperture usage at the close focus distances (0.7m thru 2m). At these portrait distances, the lens is sharpest and in focus on the rangefinder system. As a result of this wide open, minimum focus distance optimisation, the lens will focus just short of infinity wide open. Since this lens has focus shift, which causes the focal plane to move outwards as the lens is stopped down, in order to reach infinity for landscape shots, the lens should be set to f/5.6 or smaller aperture.
The reason the lens is unable to acheive infinity wide open is, if the lens was allowed to focus at infinity at f/2, then as the lens would stop down to smaller aperture, the focus shift inherent in all Sonnar formula lenses would cause the lens to focus then ‘beyond infinity’.
A simple reference to remember for using this lens with rangefinder focusing system:
Distances 0.7m to 3m – Use f/2 and f/2.8 apertures
Distanced 3m thru 10m – Use f/2.8, f/4 and f/5.6 apertures
Distances 10m thru Infinity – Use f/5.6, f/8 and smaller apertures
Thus, a nice balance between wider apertures at close distances, and smaller apertures at further distances can be acheived while using the rangefinder split patch.
Included with the lens is a screw-on ventilated hood, a rear M cap, a front push-on Zeiss cap and a screw-on 40.5mm clear BDB filter. The BDB filter does not appear to be UV coated and is mostly there to protect the front element.
The Leica camera shown in some of the photos is for reference purposes only and not included in the sale.