The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Viltrox 9mm F2.8 Z and the AstrHori 6mm f2.8 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. AstrHori 6mm f2.8 is the longer of the two lenses at 61mm. The Viltrox 9mm F2.8 Z with a length of 56mm, is 5mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 65mm.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Viltrox 9mm F2.8 Z weighs 175g, which means it is 165g (48%) lighter than the AstrHori 6mm f2.8 which has a weight of 340g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Nikon Z Mount for size comparison purposes.
Ultra-Wideangle Lenses in Nikon Z Mount for Size Comparison
Lens Mounts
Both the Viltrox 9mm F2.8 Z and the AstrHori 6mm f2.8 has the same Nikon Z lens mount. Some of the latest released cameras that are compatible with the Nikon Z lenses are RED Komodo-X 6K Z, Nikon Z50 II and Nikon Z30.
AstrHori 6mm f2.8 is also available in Sony E , Canon RF and Leica L mounts.
Focal Range
Viltrox 9mm F2.8 Z is a prime lens with fixed focal lenght of 9mm which has an effective (full-frame 35mm equivalent) focal range of
13.5mm when used on a APS-C / DX format camera.
On the other hand, the AstrHori 6mm f2.8 is a prime lens with fixed focal lenght of 6mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 9mm.