MS-Optics Perar 21mm f/4.5

The Lens

The MS Optics 21mm f/4.5 Perar is an ultra-wide pancake lens designed and hand-assembled by Sadayasu Miyazaki in Japan. It is the most well-known lens in the "Perar" series, famous for its extreme compactness. At just 5.2mm thick and weighing roughly 45 grams, the lens practically disappears when mounted, allowing even a bulky Leica M camera to slide comfortably into a jacket pocket.

Optical Design and Character

The lens utilizes a classic triplet design (three elements in three groups), a formula that dates back to the late 19th century. Miyazaki modernized it with Tantalum glass surfaces to boost performance, calling it a "Super Triplet."

The rendering is unique and polarizing.

• Sharpness: The center of the frame is surprisingly sharp, even wide open at f/4.5. However, because it is a triplet design stretching to a 21mm focal length, the corners soften significantly unless stopped down to f/8 or f/11.
• Vignetting: There is heavy light falloff in the corners (around 2-3 stops). Many users embrace this as part of the "moody" rendering, but it is technically an optical flaw.
• Digital Color Shift: On digital rangefinders (like the Leica M9, M240, or M10), the acute angle of light hitting the sensor often causes distinct magenta or green color casts in the corners. This usually requires post-processing with software like CornerFix or Flat Field plugins to correct.

Mechanics and Ergonomics

The build quality feels like a precision watch—dense and metallic—but the ergonomics are challenging due to the size.

• Aperture Control: There is no standard aperture ring. Instead, you rotate the front hood of the lens to change the f-stop. It is stepless and smooth, meaning it is easy to accidentally bump your aperture setting while focusing.
• Focusing: Focus is controlled by a small lever. It is rangefinder coupled from infinity down to roughly 0.8 meters.
• Filters: The lens is too small for standard filter threads. It uses tiny 19mm filters, which often have to be screwed into the hood or, in true MS Optics DIY fashion, glued into place by the user.

Comparison to Alternatives

The 21mm Perar is a lifestyle choice rather than a technical one.

Voigtländer 21mm f/4 Color Skopar

The Color Skopar is the practical alternative.

• Performance: The Voigtländer is technically superior. It is sharper across the frame, manages distortion better, and has far fewer issues with color shift on digital bodies.
• Handling: It functions like a normal lens with a distinct aperture ring and focus tab.
• Summary: You buy the Skopar if you want reliable, clean images. You buy the Perar if you want character and the smallest possible footprint.

Leica Elmarit-M 21mm f/2.8

The Elmarit is the professional standard.

• Size: The Leica lens is massive in comparison. You likely won't fit the camera in a pocket with an Elmarit mounted.
• Optics: The Leica offers clinical perfection, zero distortion, and even illumination across the frame. It lacks the vintage "vibe" of the Perar but delivers predictable, high-fidelity results.

MS Optics 24mm & 28mm Perars

The 21mm sits alongside longer siblings in the Perar lineup.

• The 24mm Perar is often considered the "sweet spot" of the series. It retains the pancake size but suffers less from the extreme vignetting and color shifts found on the 21mm model.
• The 21mm is wider and more dramatic, but it requires more work in post-processing to get a clean image on digital cameras.

Sources

• 35mmc
• therawcamera
• Hinting Image