MS-Optics Sonnetar 73mm f/1.5

MS-Optics Sonnetar 73mm f/1.5

Few lenses share its odd 73mm focal length, and reviewers have noted it may be the only one made at that length [1]. It is the work of Sadayasu Miyazaki, who builds MS-Optics lenses by hand in the basement of his home in Chiba, Japan, and it follows a long line of compact, often quirky designs that have earned him a cult following among rangefinder users [2]. Miyazaki described the lens as a response to the classic fast portrait optics he admired, citing the Summarex 85mm f/1.5, Summilux 75mm f/1.4, and the Canon, Nikkor, and Planar 85mm fast portrait lenses, and said he aimed to capture their character in a far smaller package [3]. The result is a notably small and light fast medium telephoto, weighing about 201 g, that pairs a wide f/1.5 aperture with an unusually portable barrel.

The optical formula is a simple Sonnar-derived design of five elements in four groups, and Miyazaki applied a multi-coating to every surface, quoting a transmission rate of about 97.5 percent. The barrel uses a unit-focus design in which the entire front section turns to focus, so the aperture ring and front element rotate together, which means it is easier to set the aperture first and then focus. Both the focus and the clickless aperture rings are smooth, and the aperture ring turns in the opposite direction to many other lenses, a trait shared with other MS-Optics designs. The lens does not feature a floating-element design and is not strongly optimized for close work, with a minimum focus distance of 0.9 m. A coma-adjustment ring sits at the rear and can be used to fine-tune the infinity hard stop, but it requires a camera spanner and can disturb the rangefinder calibration if moved. It is supplied with a 49 mm screw-in metal hood; a 49 mm filter can be fitted in place of the hood but must be mounted reversed.

There are no widely documented optical or mechanical variants of this lens. It is sometimes listed with the suffix "FMC" or "F.MC," referring to its full multi-coating. Because production is by hand and in small numbers, availability has always been limited and delivery times long, and prices on the used market have stayed high.

Optical qualities

Rendering The lens shows clear Sonnar character. Wide open it carries strong spherical aberration, sometimes described as Sonnar glow, which softens contrast before the lens sharpens up on stopping down. Miyazaki himself noted that the wide-open aperture produces soft flare suited to portraiture, with contrast and resolution improving sharply by f/1.8 and the lens reaching its best performance from f/2.8 and f/4 onward.

Sharpness Wide open there is a veil of glow across the frame that clears on stopping down; the center reaches high resolution and contrast by f/2.8, and by f/8 the lens performs well across the frame on a Leica M10. Reviewers found that a comparable Voigtlander 75mm f/1.5 delivers higher resolution and contrast at wider apertures.

Bokeh and transitions The background rendering is variable. At close focus it tends to be soft and smooth, but with more distant or structured backgrounds it can become busy and nervous, which is common with Sonnar-type lenses used wide open. At f/1.5 some reviewers also observed distracting coma- and spherical-aberration artifacts near the center of the frame.

Distortion and vignetting Distortion is very low and unlikely to be noticeable in the field, consistent with Miyazaki's stated figure of about +0.2 percent. As expected of a compact, fast lens, there is significant optical vignetting wide open, with light falloff easing as the lens is stopped down.

Flare resistance and aberrations Despite the multi-coating, the lens is prone to veiling flare and colored artifacts against bright light, and the small hood does little to suppress them. Both lateral and longitudinal chromatic aberration are pronounced, with purple fringing persisting even stopped down, which reviewers singled out as a weak point.

History

Development and Launch The Sonnetar 73mm f/1.5 was announced in 2018 as another in Miyazaki's series of handmade M-mount lenses, each typically smaller and more unusual than the last. It was distributed through specialist outlets including Japan Camera Hunter, which received early samples, and was positioned as a lightweight portrait lens with a distinctive look. Early announcements described a price of roughly ¥140,000, around 1,250 US dollars at the time, with limited numbers and long delivery times owing to the handmade process.

Collector Notes Some early launch listings carried figures that differ slightly from the confirmed specifications, including a 197 g weight, a 56.4 mm length, a 0.8 m minimum focus distance, and even conflicting filter-thread figures; the verified specifications record 201 g, 56 mm, 0.9 m, and a 49 mm filter thread. Buyers report that, as with other MS-Optics lenses on the Leica M10, the six-bit code reader may not be fully covered, which can confuse the camera under bright light; a small piece of tape over the area resolves it. Because the lenses are handmade in small batches, build consistency and rangefinder calibration are worth checking, and screws may occasionally need re-tightening. The 49 mm metal hood and the reverse-mount filter arrangement are accessories worth confirming when buying used.