SG-image MF 50mm F1.8 Shaped Aperture

The SG-image MF 50mm F1.8 Full Frame Lens with Shaped Aperture is a manual focus standard prime with a creative twist. Instead of a classic iris it uses a variable shaped aperture, so that out-of-focus highlights take on shapes such as hearts, stars or diamonds. SG-image offers it for Sony E, Fujifilm X, Nikon Z, Micro Four Thirds, Canon EF-M, Canon RF and Leica L mounts. It is designed to cover a full frame sensor and is aimed at expressive portraits and artistic shots.

Optical design

According to SG-image the lens has 7 elements in 5 groups and a 44 degree angle of view, with a maximum magnification of 1:7.7. The spec sheet lists the aperture as a variable shape aperture with one blade and a fixed aperture ring, and it gives no minimum aperture and no special glass types. The maximum opening is f/1.8.

Focusing and handling

Focusing is manual. The minimum focus distance is 0.5 m. SG-image says that when the shaped aperture lens is stopped down, out-of-focus highlights and light sources take on the specific shape, and that the lens still works as a regular standard prime. Press reports mention interchangeable aperture plates, but the product page does not describe how the shapes are changed in practice.

Build and size

The barrel is metal. The lens measures 69 mm in diameter and 48 mm in length, weighs about 311 g and takes 58 mm filters. The specification is the same for all seven mounts. Because it covers full frame, it also works on APS-C and Micro Four Thirds bodies, where the field of view is narrower.

Where it fits

Creative bokeh lenses are a niche. The Lensbaby Velvet 85mm f/1.8 in the database is another effect-oriented prime for similar mounts. For a conventional 50mm option with autofocus, SG-image's own AF 55mm F1.8 or the 7Artisans AF 50mm F1.8 (Sony E, Nikon Z) are alternatives.

Pros and cons

Pros

• Shaped bokeh as a distinctive creative effect
• Full frame coverage with F1.8 aperture
• Metal construction, 58 mm filter thread
• Minimum focus distance of 0.5 m
• Seven mounts supported

Cons

• Manual focus only
• Unusual aperture design with one blade and no conventional stop-down range published
• Special effect is not useful for every kind of shot
• No minimum aperture or glass details published
• No weather sealing mentioned

Verdict

This SG-image lens is a creative tool first and a standard prime second. It makes sense for portrait and still life photographers who enjoy playing with bokeh shapes, and its price class is low according to the maker. Anyone looking for a neutral, general purpose 50mm should pick a conventional lens instead.