The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Olympus 17mm F1.2 Pro and the Sigma 19mm F2.8 EX DN for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Olympus 17mm F1.2 Pro is the longer of the two lenses at 87mm. The Sigma 19mm F2.8 EX DN with a length of 46mm is 41mm shorter. Besides being longer, the Olympus 17mm F1.2 Pro also has a larger diameter of 68mm compared to Sigma 19mm F2.8 EX DN's 61mm 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. Sigma 19mm F2.8 EX DN weighs 140g, 64% (250g) lighter than the Olympus 17mm F1.2 Pro's weight of 390g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Micro Four Thirds Mount for size comparison purposes.
Wideangle Prime Lenses in Micro Four Thirds Mount for Size Comparison
Lens Mounts
Both Olympus 17mm F1.2 Pro and Sigma 19mm F2.8 EX DN 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-5, Panasonic GH6 and OM System OM-1.
Sigma 19mm F2.8 EX DN is also available in Sony E mount.
Focal Range
Olympus 17mm F1.2 Pro is a prime lens with fixed focal lenght of 17mm which has an effective (full-frame 35mm equivalent) focal range of 34mm when used on a FourThirds format camera. Sigma 19mm F2.8 EX DN is a prime lens with fixed focal lenght of 19mm which has an effective (full-frame 35mm equivalent) focal range of 28.5mm when used on a APS-C / DX format camera.