The type of photography that you are planning to use is an important decision factor. Here we have evaluated the OM SYSTEM 9-18mm f4.0-5.6 II and the Olympus 9mm F8 Fish-Eye 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. OM SYSTEM 9-18mm f4.0-5.6 II is the longer of the two lenses at 49mm. The Olympus 9mm F8 Fish-Eye with a length of 13mm, is 36mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 56mm.
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 9mm F8 Fish-Eye weighs 30g, 80% (124g) lighter than the OM SYSTEM 9-18mm f4.0-5.6 II's weight of 154g.
Lens Mounts
Both the OM SYSTEM 9-18mm f4.0-5.6 II and the Olympus 9mm F8 Fish-Eye 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.
Focal Range
OM SYSTEM 9-18mm f4.0-5.6 II has a focal range of 9-18mm and
2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
18-36mm when used on a FourThirds format camera.
On the other hand, the Olympus 9mm F8 Fish-Eye is a prime lens with fixed focal lenght of 9mm which has an effective (full-frame 35mm equivalent) focal range of 18mm when used on a FourThirds format camera.