Voigtländer APO-LANTHAR 90mm f/3.5

Voigtländer APO-LANTHAR 90mm f/3.5

This was the longest of the four lenses Cosina released under the revived Voigtländer name to accompany the Bessa-R rangefinder around 2000, joining the 35mm f/1.7 Ultron, 50mm f/1.5 Nokton and 75mm f/2.5 Color-Heliar [1]. Where the Bessa bodies of the era leaned heavily on plastic, the lenses were built entirely of metal to a high standard, and the APO-Lanthar carried the most ambitious billing of the group: an apochromatic medium telephoto in Leica thread mount, a configuration that few makers were offering when it appeared[2]. It remains one of the most modern telephoto designs available in LTM, and its small size and low weight have made it a favorite for travel and hiking kits[4].

The optical formula uses six elements in five groups and includes a low-dispersion element to suppress chromatic aberration, which is the basis of the lens's APO claim. It focuses to one metre, stops down through ten aperture blades, and the diaphragm ring runs in half-stop clicks. The barrel extends slightly as it focuses toward its closest distances. The focus ring is well damped, and the build includes neatly machined controls plus a knurled ring near the mount that helps when threading the lens on and off. The lens accepts 39mm filters, and its screw-in metal hood is designed to stay on the lens; the front cap slides onto the hood rather than threading into the barrel. Being LTM, it couples to the rangefinder and adapts easily to Leica M bodies and to mirrorless cameras through inexpensive adapters, where it is used in manual focus and working-aperture mode. A separate APO-Lanthar 90mm f/3.5 was later produced in SL and SL II form for SLR mounts such as Canon EF, Nikon F and Pentax K; despite the shared name and focal length, that lens uses a different optical and mechanical design and is not the rangefinder version described here[3].

Optical qualities

Rendering Reviewers and users consistently describe the lens as sharp from its maximum aperture with strong resolving power and pleasing color, in line with its apochromatic design and the low-dispersion element it contains. Some debate exists about whether the modern lens truly continues the rare-earth "Lanthar" lineage of the original Voigtländer Lanthar lenses, but its corrected, high-contrast output is widely acknowledged.

Sharpness Center sharpness is reported as excellent wide open at f/3.5, with the frame improving slightly around f/5.6; diffraction softens the image noticeably by the smallest apertures such as f/16 [5].

Bokeh and transitions At f/3.5 the depth of field is moderate rather than thin, so background separation is described as reasonable and the out-of-focus rendering as generally smooth; opinions on the bokeh vary, with some users noting bright-edged highlights in certain conditions.

Flare resistance The supplied metal hood is recommended for everyday use, as the lens is more prone to flare without it and the protruding front element benefits from the protection.

Digital use The lens adapts readily to mirrorless cameras, where magnified live view aids accurate manual focusing; on cropped sensors the field of view is roughly equivalent to a 135mm lens.

History

Development and Launch The lens arrived as part of Cosina's revival of the Voigtländer brand, launched alongside the Bessa-R, a rangefinder with TTL metering and frame lines for 35, 50, 75 and 90mm. The accompanying lens suite was clearly aimed at the Leica-compatible market, exploiting the close compatibility between LTM and M-mount, and the 90mm f/3.5 served as the long end of that initial range.

Production Evolution The rangefinder APO-Lanthar 90mm f/3.5 has been offered in black and silver finishes. A differently designed APO-Lanthar 90mm f/3.5 for SLR mounts followed, with an SL II version announced by Voigtländer in 2010; that SLR lens uses its own optical and mechanical layout and should not be conflated with the LTM lens.

Collector Notes Buyers should be aware that fungus on the front elements has been reported as a relatively common issue with this lens, so inspecting the glass before purchase is advised. Because the name is shared with the SLR APO-Lanthar 90mm f/3.5 (SL and SL II), confirm the mount and that the lens is the LTM rangefinder version, which has a 39mm filter thread and the slide-on hood with matching cap. Note also that published references differ on element and blade counts between the rangefinder and SLR designs; the LTM lens described here uses six elements in five groups with ten aperture blades.