Kase AF 150mm F5.6 Reflex

The Kase AF 150mm F5.6 Reflex is an autofocus mirror lens for full frame cameras. Kase describes it as the first mirror telephoto lens with autofocus. It is offered for Nikon Z, Sony E, Canon EF and Fujifilm G. As with other reflex lenses, it uses a catadioptric design that folds the light path, which keeps a 150 mm lens short, and it is known for its ring-shaped "donut" bokeh. Kase says it is the shortest 150 mm lens on the market.

Optical design

The optical design has 5 elements in 4 groups. Because it is a mirror lens, the aperture is fixed at f/5.6 and there is no adjustable iris. The closest focus distance is 1.5 m. A 67 mm filter thread is fitted, and the front also takes Kase's magnetic filters through a magnetic front ring. The format is full frame.

Autofocus and handling

The lens is a native autofocus design with an AF/MF switch on the barrel and a grooved focus ring for manual adjustment. A USB-C port inside the barrel allows firmware updates. Kase notes that a magnetic pinch lens cap can stay on even when the hood is attached, so the lens is ready to use quickly. There is no image stabilization in the lens.

Build and size

The body is made of aluminium alloy, as stated by Kase. Kase emphasises that the lens is compact and meant for handheld shooting.

Where it fits

Within Kase's own range, the 200mm F5.6 MC Reflex is the manual focus relative with a longer focal length. Other mirror lenses in the database are the Samyang / Rokinon Reflex 300mm F6.3 ED UMC CS, the Tokina SZX Super Tele 400mm F8 Reflex MF and the TTArtisan 500mm f/6.3, all manual focus designs with longer focal lengths. The 150 mm focal length makes the Kase a shorter and more usable telephoto in comparison.

Pros and cons

Pros

• Autofocus in a mirror lens
• Compact telephoto with the distinctive donut bokeh
• 67 mm thread plus magnetic filter ring
• USB-C firmware updates
• Offered for four mounts, including Fujifilm G

Cons

• Fixed f/5.6 aperture
• Minimum focus distance of 1.5 m
• No image stabilization

Verdict

The Kase AF 150mm F5.6 Reflex is a creative telephoto for photographers who want the look of a mirror lens without manual focusing. It remains a niche lens with a fixed aperture, and its appeal is the combination of compact size and autofocus.