The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 24mm F1.8 EX DG and the Olympus M 25mm F1.8 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 24mm F1.8 EX DG is the longer of the two lenses at 83mm. The Olympus M 25mm F1.8 with a length of 41mm, is 42mm shorter. Besides being longer, the Sigma 24mm F1.8 EX DG also has a larger diameter of 84mm compared to the Olympus M 25mm F1.8'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. Olympus M 25mm F1.8 weighs 136g, 71% (349g) lighter than the Sigma 24mm F1.8 EX DG's weight of 485g.
Filter Threads
The Sigma 24mm F1.8 EX DG has a filter size of 77mm whereas the Olympus M 25mm F1.8 has a 46mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Sigma 24mm F1.8 EX DG:
And these are the 46mm filters that we recommend for the Olympus M 25mm F1.8:
Lens Mounts
The Sigma 24mm F1.8 EX DG has the Four Thirds lens mount whereas the Olympus M 25mm F1.8 has the Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with these mounts are Olympus E-5, Olympus E-600 and Olympus E-620 for the Four Thirds Mount and OM System OM-3 Astro, OM System OM-5 II and OM System OM-3 for the Micro Four Thirds Mount.
Sigma 24mm F1.8 EX DG is also available in the Canon EF , Nikon F (FX), Pentax KAF, Sony Alpha, Sigma SA, Canon EF, Pentax KAF, Sony Alpha, Sigma SA and Nikon F (FX) mounts.
Focal Range
Sigma 24mm F1.8 EX DG is a prime lens with fixed focal lenght of 24mm.
On the other hand, the Olympus M 25mm F1.8 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.
