The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 30mm F1.4 EX DC HSM and the Pentax 18-55mm F3.5-5.6 AL WR 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. Pentax 18-55mm F3.5-5.6 AL WR is the longer of the two lenses at 68mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 9mm shorter. On the other hand, the Sigma 30mm F1.4 EX DC HSM has a larger diameter of 77mm compared to the Pentax 18-55mm F3.5-5.6 AL WR's 69mm 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. Pentax 18-55mm F3.5-5.6 AL WR weighs 230g, 46% (200g) lighter than the Sigma 30mm F1.4 EX DC HSM's weight of 430g.
Filter Threads
The Sigma 30mm F1.4 EX DC HSM has a filter size of 62mm whereas the Pentax 18-55mm F3.5-5.6 AL WR has a 52mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 62mm filters that we recommend you to consider for the Sigma 30mm F1.4 EX DC HSM:
And these are the 52mm filters that we recommend for the Pentax 18-55mm F3.5-5.6 AL WR:
Lens Mounts
Both the Sigma 30mm F1.4 EX DC HSM and the Pentax 18-55mm F3.5-5.6 AL WR has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Sigma 30mm F1.4 EX DC HSM is also available in the Canon EF-S , Nikon F (DX), Four Thirds, Sony Alpha and Sigma SA mounts.
Focal Range
Sigma 30mm F1.4 EX DC HSM is a prime lens with fixed focal lenght of 30mm which has an effective (full-frame 35mm equivalent) focal range of
45mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 18-55mm F3.5-5.6 AL WR has a focal range of 18-55mm and 3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-82.5mm when used on a APS-C / DX format camera.
