The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-50mm F2.8 DC DN C and the Sigma 30mm F1.4 EX DC 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 DC DN C is the longer of the two lenses at 77mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 18mm 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 DC DN C's 62mm 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 DC DN C weighs 285g, which means it is 145g (33%) lighter than the Sigma 30mm F1.4 EX DC HSM which has a weight of 430g.
Filter Threads
The Sigma 18-50mm F2.8 DC DN C has a filter size of 55mm whereas the Sigma 30mm F1.4 EX DC HSM has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 55mm filters that we recommend you to consider for the Sigma 18-50mm F2.8 DC DN C:
And these are the 62mm filters that we recommend for the Sigma 30mm F1.4 EX DC HSM:
Lens Mounts
The Sigma 18-50mm F2.8 DC DN C has the Fujifilm X lens mount whereas the Sigma 30mm F1.4 EX DC HSM has the Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount and Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount.
Sigma 18-50mm F2.8 DC DN C is also available in the Leica L and Sony E mounts.
Sigma 30mm F1.4 EX DC HSM is also available in Canon EF-S , Four Thirds, Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Sigma 18-50mm F2.8 DC DN C 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.
On the other hand, the 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.