The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Zeiss Otus 50mm f1.4 and the Sigma 18-50mm F2.8 DC DN C RF 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. Zeiss Otus 50mm f1.4 is the longer of the two lenses at 100mm. The Sigma 18-50mm F2.8 DC DN C RF with a length of 75mm, is 25mm shorter. Besides being longer, the Zeiss Otus 50mm f1.4 also has a larger diameter of 77mm compared to the Sigma 18-50mm F2.8 DC DN C RF'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. Sigma 18-50mm F2.8 DC DN C RF weighs 300g, 55% (377g) lighter than the Zeiss Otus 50mm f1.4's weight of 677g.
Filter Threads
The Zeiss Otus 50mm f1.4 has a filter size of 67mm whereas the Sigma 18-50mm F2.8 DC DN C RF has a 55mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Zeiss Otus 50mm f1.4:
And these are the 55mm filters that we recommend for the Sigma 18-50mm F2.8 DC DN C RF:
Lens Mounts
Both the Zeiss Otus 50mm f1.4 and the Sigma 18-50mm F2.8 DC DN C RF has the same Canon RF lens mount. Some of the latest released cameras that are compatible with the Canon RF lenses are Canon R6 V, Canon R6 III and Canon C50.
Zeiss Otus 50mm f1.4 is also available in the Sony E and Nikon Z mounts.
Focal Range
Zeiss Otus 50mm f1.4 is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
75mm.
On the other hand, the Sigma 18-50mm F2.8 DC DN C RF has a focal range of 18-50mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 28.8-80mm when used on a APS-C / DX format camera.
