The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Irix 45mm F1.4 and the Sigma 50mm F1.4 DG HSM A for their suitability to various photography scenarios:
Size and Weight Comparison
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 50mm F1.4 DG HSM A weighs 815g, 11% (110g) lighter than the Irix 45mm F1.4's weight of 925g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Nikon F (FX) Mount for size comparison purposes.
Standard Lenses in Nikon F (FX) Mount for Size Comparison
Filter Threads
Both the Irix 45mm F1.4 and the Sigma 50mm F1.4 DG HSM A have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Irix 45mm F1.4 and the Sigma 50mm F1.4 DG HSM A has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Irix 45mm F1.4 is also available in the Canon EF and Pentax KAF2 mounts.
Sigma 50mm F1.4 DG HSM A is also available in Canon EF , Sony Alpha, Sigma SA and Leica L mounts.
Focal Range
Irix 45mm F1.4 is a prime lens with fixed focal lenght of 45mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
67.5mm.
On the other hand, the Sigma 50mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 75mm.
