Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 30mm F1.4 C is the longer of the two lenses at 73mm. The Olympus 30mm F3.5 Macro with a length of 60mm is 13mm shorter. Besides being longer, the Sigma 30mm F1.4 C also has a larger diameter of 65mm compared to Olympus 30mm F3.5 Macro's 57mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Olympus 30mm F3.5 Macro weighs 128g, which means it is 137g (107%) lighter than the Sigma 30mm F1.4 C which has a weight of 265g.
Both Olympus 30mm F3.5 Macro and Sigma 30mm F1.4 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 Panasonic GH6, OM System OM-1 and Panasonic GH5 II.
Sigma 30mm F1.4 C is also available in Sony E and Fujifilm X mounts.