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 Sigma 18-50mm F2.8-4.5 DC OS HSM 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 18-50mm F2.8-4.5 DC OS HSM is the longer of the two lenses at 89mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 30mm shorter. On the other hand, the Sigma 30mm F1.4 EX DC HSM has a larger diameter of 77mm compared to the Sigma 18-50mm F2.8-4.5 DC OS HSM's 74mm 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. Sigma 18-50mm F2.8-4.5 DC OS HSM weighs 395g, 8% (35g) 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 Sigma 18-50mm F2.8-4.5 DC OS HSM has a 67mm 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 67mm filters that we recommend for the Sigma 18-50mm F2.8-4.5 DC OS HSM:
Lens Mounts
Both the Sigma 30mm F1.4 EX DC HSM and the Sigma 18-50mm F2.8-4.5 DC OS HSM has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A68, Sony A77 II and Sony A58.
Sigma 30mm F1.4 EX DC HSM is also available in the Canon EF-S , Nikon F (DX), Four Thirds, Pentax KAF and Sigma SA mounts.
Sigma 18-50mm F2.8-4.5 DC OS HSM is also available in Canon EF , Pentax KAF3, Sigma SA and Nikon F (DX) 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 Sigma 18-50mm F2.8-4.5 DC OS HSM has a focal range of 18-50mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-75mm when used on a APS-C / DX format camera.
