The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 17-70mm F2.8-4 DC OS HSM C and the Olympus ED 40-150mm f4.0-5.6 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 17-70mm F2.8-4 DC OS HSM C is the longer of the two lenses at 82mm. The Olympus ED 40-150mm f4.0-5.6 with a length of 72mm, is 10mm shorter. Besides being longer, the Sigma 17-70mm F2.8-4 DC OS HSM C also has a larger diameter of 79mm compared to the Olympus ED 40-150mm f4.0-5.6's 66mm 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 ED 40-150mm f4.0-5.6 weighs 220g, 52% (245g) lighter than the Sigma 17-70mm F2.8-4 DC OS HSM C's weight of 465g.
Filter Threads
The Sigma 17-70mm F2.8-4 DC OS HSM C has a filter size of 72mm whereas the Olympus ED 40-150mm f4.0-5.6 has a 58mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 72mm filters that we recommend you to consider for the Sigma 17-70mm F2.8-4 DC OS HSM C:
And these are the 58mm filters that we recommend for the Olympus ED 40-150mm f4.0-5.6:
Lens Mounts
The Sigma 17-70mm F2.8-4 DC OS HSM C has the Pentax KAF3 lens mount whereas the Olympus ED 40-150mm f4.0-5.6 has the Four Thirds lens mount. Some of the latest released cameras that are compatible with these mounts are , and for the Pentax KAF3 Mount and Olympus E-5, Olympus E-600 and Olympus E-620 for the Four Thirds Mount.
Sigma 17-70mm F2.8-4 DC OS HSM C is also available in the Canon EF , Sony Alpha, Sigma SA and Nikon F (DX) mounts.
Focal Range
Sigma 17-70mm F2.8-4 DC OS HSM C has a focal range of 17-70mm and
4.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.5-105mm when used on a APS-C / DX format camera.
On the other hand, the Olympus ED 40-150mm f4.0-5.6 has a focal range of 40-150mm and 3.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 80-300mm when used on a FourThirds format camera.
