MS-Optics Perar 17mm f/4.5

The Lens

The MS Optics 17mm f/4.5 Perar is a manual focus, ultra-wide angle prime lens for the Leica M mount, released by the boutique Japanese manufacturer MS Optics (Miyazaki Optical). Known for its extreme compactness, the lens is the creation of Sadayasu Miyazaki, who hand-assembles these optics in limited batches. The lens is characterized by its "pancake" profile, measuring roughly 10.2mm in length, effectively turning a full-frame rangefinder camera into a pocketable point-and-shoot system.

Optical Design and Performance

Unlike many previous "Perar" lenses which utilized triplet formulas, the 17mm f/4.5 employs a retrofocus design with four elements in four groups. This choice allows for a wider field of view (100 degrees diagonal) while attempting to mitigate some of the severe corner smearing often seen in symmetrical wide-angle lenses on digital sensors.

• Sharpness: The lens exhibits strong central sharpness from its maximum aperture of f/4.5. However, the mid-frame and corners suffer from significant field curvature and astigmatism. To achieve acceptable sharpness across the frame, users typically need to stop the lens down to f/11 or f/16.
• ** distortion and Vignetting:** The lens produces distinct "wavy" (mustache) distortion, which can be difficult to correct in post-processing without specialized profiles. Vignetting is also prominent, with light falloff measuring nearly 4 EV in the corners at wide apertures.
• Digital Sensor Characteristics: On digital bodies (such as the Leica M10 or Sony Alpha series), the lens often introduces color shifts in the corners (magenta or green casts) due to the acute angle of light hitting the sensor.

Mechanical Construction

The build quality reflects the idiosyncratic nature of MS Optics. The barrel is machined from aluminum and weighs a mere 47 grams. The focusing mechanism is a rotating lever that moves the entire optical block.

• Aperture: The aperture is controlled by a small inner ring near the front element. It lacks click stops and can be difficult to adjust without accidentally moving the focus lever or getting fingerprints on the glass. The lens uses a 10-blade diaphragm, which produces well-defined sunstars.
• Filters: The lens does not have a standard filter thread. Instead, the manufacturer suggests users salvage the glass from a 34mm filter and glue it to the front of the lens hood, a unique DIY requirement typical of Miyazaki's designs.

Comparison to Alternatives

The MS Optics 17mm occupies a niche for photographers prioritizing size above all else, standing in contrast to mainstream alternatives.

Voigtländer Super-Wide Heliar 15mm f/4.5 III

The Voigtländer 15mm Version III is the standard benchmark for modern ultra-wide rangefinder lenses.

• Optics: The Voigtländer is optically superior in almost every metric. It is fully corrected for digital sensors (eliminating color shifts), has negligible distortion, and is sharp across the frame at wider apertures.
• Size: The trade-off is physical bulk. The Voigtländer is significantly larger and heavier than the wafer-thin Perar.
• Use Case: The Voigtländer is a professional tool for architecture and landscapes; the Perar is a character lens for street photography and travel.

MS Optics Hipolion 19mm f/8

The Hipolion is an even simpler, more experimental lens from the same designer.

• Speed: The Perar (f/4.5) is significantly faster than the Hipolion (f/8), making it more usable in lower light or for handheld shooting.
• Design: The Hipolion uses a 2-element design and is essentially a glorified body cap. The Perar, with its 4-element retrofocus formula, offers better optical performance and a wider field of view.

MS Optics Perar 21mm f/4.5 (and 24mm)

The 21mm and 24mm variants are the siblings in the "Perar" line, usually utilizing triplet designs.

• Focal Length: The 17mm is significantly wider (100 degrees vs roughly 90 degrees for the 21mm), creating a more dramatic perspective but introducing more difficult distortion.
• Handling: The 21mm and 24mm versions generally suffer less from the extreme corner color shifts seen on the 17mm due to the less aggressive focal length, though they share similar ergonomic quirks like the fiddly aperture adjustment.

Sources:

• Phillip Reeve