Kase AF 85mm F1.4

The Kase AF 85mm F1.4 is a full frame autofocus portrait prime and the first autofocus lens from the filter maker Kase. It is offered for Sony E, Nikon Z, Fujifilm X and Leica L. Its main distinguishing feature is a magnetic filter ring built into the front of the lens, which takes Kase's Revolution and Revolution Plus magnetic filters without a separate adapter ring. Kase positions it for portraits, low-light work and video.

Optical design

Kase specifies 13 elements in 10 groups, including 5 low-dispersion elements and 2 high-refractive-index elements. The diaphragm has 13 blades, and the aperture range is f/1.4 to f/16. The closest focus distance is 0.7 m. The lens covers the full frame format. There is no image stabilization in the lens, so stabilized camera bodies are needed to compensate for shake.

Autofocus and handling

Autofocus is driven by an STM motor, with an AF/MF switch for manual focusing. The lens has two customizable function buttons: according to Kase, the second one is set to jump to the minimum focus distance with a short press and to lock the current focus distance with a long press. An aperture ring with click stops is combined with a click/declick switch, and an A position sets f/1.4. A USB-C port at the bottom allows firmware updates. Kase notes that the Sony E version comes with a clip-in Magic Filter (ND).

Build and size

The body combines aluminium alloy, polycarbonate and optical glass. Kase gives a weight of 580 g, 610 g with the hood, at 82 mm diameter and 99 mm length. The filter thread is 72 mm and comes with an inlaid adapter for the magnetic filters. A magnetic lens cap is included, and Kase specifies an operating temperature range of -40 to 60 degrees Celsius.

Where it fits

In the 85 mm f/1.4 class for these systems, the Viltrox AF 85mm F1.4 Pro (Sony E and Nikon Z), the Sirui Aurora 85mm F1.4 and the Samyang / Rokinon AF 85mm F1.4 FE are direct competitors, and the Sony FE 85mm F1.4 GM II sits at the top of the class. The Kase differs mainly through its integrated magnetic filter system.

Pros and cons

Pros

• Integrated magnetic filter ring
• 13-blade diaphragm and f/1.4 maximum aperture
• Two function buttons and a click/declick switch
• USB-C firmware updates
• Four mounts

Cons

• No image stabilization
• STM motor rather than a linear or voice coil motor
• 580 g, rather heavy for an APS-C body
• Minimum focus distance of 0.7 m

Verdict

The Kase AF 85mm F1.4 is a full frame portrait lens for photographers who use filters heavily and like the idea of a magnetic filter ring on the lens itself. Optically it follows the usual recipe of this class, so its appeal lies mostly in the handling features.