The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 4.5mm F2.8 EX DC HSM Fisheye and the Carl Zeiss Apo Sonnar T2/135 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 Apo Sonnar T2/135 is the longer of the two lenses at 128mm. The Sigma 4.5mm F2.8 EX DC HSM Fisheye with a length of 78mm, is 50mm shorter. Besides being longer, the Carl Zeiss Apo Sonnar T2/135 also has a larger diameter of 84mm compared to the Sigma 4.5mm F2.8 EX DC HSM Fisheye's 76mm 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. Sigma 4.5mm F2.8 EX DC HSM Fisheye weighs 470g, which means it is 450g (48%) lighter than the Carl Zeiss Apo Sonnar T2/135 which has a weight of 920g.
Lens Mounts
The Sigma 4.5mm F2.8 EX DC HSM Fisheye has the Sigma SA lens mount whereas the Carl Zeiss Apo Sonnar T2/135 has the Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with these mounts are Sigma SD1 Merrill, Sigma SD1 and for the Sigma SA Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount.
Sigma 4.5mm F2.8 EX DC HSM Fisheye is also available in the Canon EF and Nikon F (DX) mounts.
Carl Zeiss Apo Sonnar T2/135 is also available in Canon EF mount.
Focal Range
Sigma 4.5mm F2.8 EX DC HSM Fisheye is a prime lens with fixed focal lenght of 5mm which has an effective (full-frame 35mm equivalent) focal range of
7.5mm when used on a APS-C / DX format camera.
On the other hand, the Carl Zeiss Apo Sonnar T2/135 is a prime lens with fixed focal lenght of 135mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 202.5mm.
