AstrHori 6mm f/2.8 Circular Fisheye

The AstrHori 6mm f/2.8 Circular Fisheye is a manual-focus circular fisheye for full-frame mirrorless cameras, offered for Sony E, Leica L, Canon RF and Nikon Z. Instead of filling the rectangular frame, it records a circular image with a 220 degree angle of view, which covers more than a hemisphere. AstrHori recommends it for urban scenes, astrophotography, street and portrait experiments, landscapes and video.

Optical design

The lens has 10 elements in eight groups. The eight-blade aperture runs from f/2.8 to f/16, and the angle of view is 220 degrees. The minimum focusing distance is only 0.08 m, which AstrHori presents as a way to combine strong edge distortion with subjects placed very close to the lens, similar to wide-angle macro shots.

Focusing and handling

Focusing is manual. The barrel carries a focus ring, an aperture ring with click stops and a depth-of-field indicator. There is no autofocus and no stabilizer. According to AstrHori, f/2.8 combined with the 220 degree view can capture the night sky and the Milky Way in one frame without stitching, and a central position of the pole star gives concentric star trails.

Build and size

The finish is matte black. In its Sony E version the lens measures 64.8 mm in diameter and 61 mm in length, and it weighs about 340 g.

Where it fits

In this database, the Sigma 8mm F3.5 EX DG Circular Fisheye and the Sigma 4.5mm F2.8 EX DC HSM Circular Fisheye are circular fisheyes for Canon EF and Nikon F. For full-frame mirrorless fisheyes with a full rectangular frame there are the AstrHori 12mm f/2.8 Fisheye, the Venus Laowa 4mm F2.8 Fisheye and the 7artisans Photoelectric 10mm f/2.8 Fisheye. The AstrHori 6.5mm f/2 Fisheye is an APS-C counterpart from the same maker.

Pros and cons

Pros

• 220 degree angle of view on full frame
• Minimum focusing distance of 0.08 m
• f/2.8 maximum aperture for night work
• Aperture ring with clicks and a depth-of-field indicator

Cons

• Circular image means large unused areas of the sensor
• Extreme distortion by design
• Manual focus and manual aperture only

Verdict

The AstrHori 6mm f/2.8 Circular Fisheye is a specialist lens for creative full-frame photographers and video makers who want the circular look. It offers an extreme view and very close focus, while everyday use is limited by the circular format.