Leica Elmar 50mm f/3.5 LTM Red Scale (1951)

Leica Elmar 50mm f/3.5 LTM Red Scale (1951)

The Leica Elmar 50mm f/3.5 LTM Red Scale is a collapsible standard lens introduced in 1951 for Leica screw-mount rangefinder cameras. It represents the final major form of the classic f/3.5 Elmar in Leica Thread Mount and is distinguished by red-filled depth-of-field markings, revised scale placement and a late coated optical configuration. It remains historically important as the last major development of the compact Elmar design before the faster Elmar 50mm f/2.8 replaced it in Leica's normal-lens range .

The lens uses a four-element, three-group optical construction and a ten-blade diaphragm operating from f/3.5 to f/22. Its chrome-plated brass barrel collapses into compatible Leica screw-mount camera bodies for transport. The focusing mount is rangefinder coupled, locks at infinity and focuses down to 1 metre. Filters and accessories attach through the A36 clamp-on standard rather than a conventional 36mm threaded filter mount.

The Red Scale version should be separated from the earlier black-scale chrome Elmar. Collector references describe a recomputed design beginning around serial number 905000, accompanied by changes in optical glass and element curvature. The visible identification changes include red depth-of-field figures and the reversal of the focusing-distance and depth-of-field scale positions. However, black-scale and Red Scale production overlapped, so production year or serial number alone should not be used without inspecting the physical markings.

Optical qualities

Rendering

The Red Scale Elmar retains the compact four-element, three-group architecture associated with the classic Elmar family. Leica describes the 50mm f/3.5 Elmar as producing good central definition at full aperture, with weaker outer zones that improve when the lens is stopped down.

Sharpness

The lens is strongest in the central image area at wider apertures. Stopping down improves the outer field and overall uniformity. Specialist historical references place peak general performance around f/8, although the condition and optical alignment of individual surviving examples can materially influence results.

Contrast and color

The Red Scale Elmar was produced as a coated lens. Its coating and limited number of air-to-glass surfaces support better contrast in difficult lighting than an early uncoated Elmar. Actual performance depends heavily on coating condition, internal haze, cleaning damage and previous servicing.

Flare resistance

The A36 FISON hood is the period accessory normally associated with this lens. Hood use is advisable because front-element cleaning marks, coating deterioration and internal haze can reduce contrast and increase veiling flare.

Digital use

The lens can be mounted on a Leica M camera with a correctly manufactured 50mm LTM-to-M adapter. Because it is collapsible, clearance should be checked before retracting the barrel into any digital or film M body. The lens should not be collapsed when compatibility is uncertain.

History

Development and Launch

The original 50mm f/3.5 Elmar design became Leica's principal standard lens during the screw-mount era. In 1951 Leitz introduced the form now commonly called the Red Scale Elmar, beginning around serial number 905000 according to specialist collector research.

The revised lens retained the established 50mm focal length, f/3.5 maximum aperture, collapsible construction and one-metre minimum focusing distance. The most visible changes were the red-filled depth-of-field figures and the reversed placement of the distance and depth-of-field scales.

Production Evolution

Early Red Scale lenses were produced in Leica Thread Mount with metric or foot distance scales. Some collector references distinguish early examples by a diamond-shaped focus index and later examples by a triangular index. These are identification variations within the Red Scale family rather than separate optical models.

Later production continued alongside the native Leica M-bayonet Elmar. Screw-mount examples must therefore be distinguished from M-mount lenses and from LTM lenses carrying a removable M adapter.

Special Editions/Variants

An Esercito Italiano version with Italian Army engraving is documented. Rare black-finished Elmars with white engravings were also made to accompany a limited group of black Leica IIIf cameras. No separate numerical model number is confirmed for either variation.

Older Elmars could be returned to Leitz for coating, repolishing, recalibration or mechanical updating. A lens with modified red markings or a replacement barrel may therefore not retain its original optical cell or original production appearance.

Collector Notes

A genuine production Red Scale Elmar normally displays red-filled depth-of-field markings and the reversed scale arrangement associated with the late version. The serial number is engraved in small figures near the front aperture-control area and should be inspected with magnification.

Collectors should not classify a lens solely by its year. Red Scale and black-scale examples overlap in documented serial-number blocks, and Leitz offered factory servicing that could alter coatings, engravings or mechanical components.

The lens should be inspected for front-element cleaning marks, coating damage, internal haze, fungus and separation in the cemented rear group. The collapsible tube should extend smoothly and lock firmly. The infinity lock, focusing helicoid, aperture tab and rangefinder cam should operate without excessive resistance.