The type of photography that you are planning to use is an important decision factor. Here we have evaluated the OM System 25mm F1.8 II and the Sigma 56mm F1.4 DC DN C 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 56mm F1.4 DC DN C is the longer of the two lenses at 60mm. The OM System 25mm F1.8 II with a length of 41mm, is 19mm shorter. Besides being longer, the Sigma 56mm F1.4 DC DN C also has a larger diameter of 67mm compared to the OM System 25mm F1.8 II's 56mm 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 System 25mm F1.8 II weighs 156g, which means it is 124g (44%) lighter than the Sigma 56mm F1.4 DC DN C which has a weight of 280g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Micro Four Thirds Mount for size comparison purposes.
Standard Lenses in Micro Four Thirds Mount for Size Comparison
Filter Threads
The OM System 25mm F1.8 II has a filter size of 46mm whereas the Sigma 56mm F1.4 DC DN C has a 55mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 46mm filters that we recommend you to consider for the OM System 25mm F1.8 II:
And these are the 55mm filters that we recommend for the Sigma 56mm F1.4 DC DN C:
Lens Mounts
Both the OM System 25mm F1.8 II and the Sigma 56mm F1.4 DC DN C has the same Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with the Micro Four Thirds lenses are OM System OM-3 Astro, OM System OM-5 II and OM System OM-3.
Sigma 56mm F1.4 DC DN C is also available in Sony E and Leica L mounts.
Focal Range
OM System 25mm F1.8 II is a prime lens with fixed focal lenght of 25mm which has an effective (full-frame 35mm equivalent) focal range of
50mm when used on a FourThirds format camera.
On the other hand, the Sigma 56mm F1.4 DC DN C is a prime lens with fixed focal lenght of 56mm which has an effective (full-frame 35mm equivalent) focal range of 112mm when used on a APS-C / DX format camera.
