The type of photography that you are planning to use is an important decision factor. Here we have evaluated the OM ED 20mm F1.4 Pro and the Sigma 50mm F1.4 EX DG HSM 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. Sigma 50mm F1.4 EX DG HSM is the longer of the two lenses at 68mm. The OM ED 20mm F1.4 Pro with a length of 62mm, is 6mm shorter. Besides being longer, the Sigma 50mm F1.4 EX DG HSM also has a larger diameter of 85mm compared to the OM ED 20mm F1.4 Pro's 63mm 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. OM ED 20mm F1.4 Pro weighs 247g, which means it is 258g (51%) lighter than the Sigma 50mm F1.4 EX DG HSM which has a weight of 505g.
Filter Threads
The OM ED 20mm F1.4 Pro has a filter size of 58mm whereas the Sigma 50mm F1.4 EX DG HSM has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the OM ED 20mm F1.4 Pro:
And these are the 77mm filters that we recommend for the Sigma 50mm F1.4 EX DG HSM:
Lens Mounts
The OM ED 20mm F1.4 Pro has the Micro Four Thirds lens mount whereas the Sigma 50mm F1.4 EX DG HSM has the Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with these mounts are OM System OM-3 Astro, OM System OM-5 II and OM System OM-3 for the Micro Four Thirds Mount and , and for the Pentax KAF3 Mount.
Sigma 50mm F1.4 EX DG HSM is also available in Canon EF , Sony Alpha, Sigma SA, Nikon F (FX) and Four Thirds mounts.
Focal Range
OM ED 20mm F1.4 Pro is a prime lens with fixed focal lenght of 20mm which has an effective (full-frame 35mm equivalent) focal range of
40mm when used on a FourThirds format camera.
On the other hand, the Sigma 50mm F1.4 EX DG HSM 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.
