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 56mm F1.4 C 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 56mm F1.4 C with a length of 60mm, is 17mm shorter. On the other hand, the Sigma 56mm F1.4 C has a larger diameter of 67mm 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 56mm F1.4 C weighs 280g, 1% (5g) lighter than the Sigma 18-50mm F2.8 DC DN C's weight of 285g.
Filter Threads
Both the Sigma 18-50mm F2.8 DC DN C and the Sigma 56mm F1.4 C have the same Filter thread size of 55mm.
Below are links to the 55mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 18-50mm F2.8 DC DN C and the Sigma 56mm F1.4 C has the same Fujifilm X lens mount. Some of the latest released cameras that are compatible with the Fujifilm X lenses are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5.
Sigma 18-50mm F2.8 DC DN C is also available in the Leica L and Sony E mounts.
Sigma 56mm F1.4 C is also available in Nikon Z and Canon RF 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 56mm F1.4 C is a prime lens with fixed focal lenght of 56mm which has an effective (full-frame 35mm equivalent) focal range of 84mm when used on a APS-C / DX format camera.