The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Rokinon 8mm f3.5 Fisheye and the Carl Zeiss Distagon T3,5/18 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. Carl Zeiss Distagon T3,5/18 is the longer of the two lenses at 84mm. The Rokinon 8mm f3.5 Fisheye with a length of 77mm, is 7mm shorter. Besides being longer, the Carl Zeiss Distagon T3,5/18 also has a larger diameter of 87mm compared to the Rokinon 8mm f3.5 Fisheye's 75mm diameter.
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. Rokinon 8mm f3.5 Fisheye weighs 443g, which means it is 27g (5%) lighter than the Carl Zeiss Distagon T3,5/18 which has a weight of 470g.
Below you can find the dimension and weight table of the Wideangle Fisheye Prime Lenses in Pentax KAF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Pentax KAF Mount for Size Comparison
Lens Mounts
Both the Rokinon 8mm f3.5 Fisheye and the Carl Zeiss Distagon T3,5/18 has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Rokinon 8mm f3.5 Fisheye is also available in the Canon EF , Nikon F (FX), Four Thirds, Sony Alpha and Samsung NX mounts.
Carl Zeiss Distagon T3,5/18 is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Rokinon 8mm f3.5 Fisheye is a prime lens with fixed focal lenght of 8mm which has an effective (full-frame 35mm equivalent) focal range of
12mm when used on a APS-C / DX format camera.
On the other hand, the Carl Zeiss Distagon T3,5/18 is a prime lens with fixed focal lenght of 18mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 27mm.
