The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 600mm F4 GM and the Sigma 105mm F1.4 DG 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. Sony FE 600mm F4 GM is the longer of the two lenses at 449mm. The Sigma 105mm F1.4 DG HSM with a length of 132mm, is 317mm shorter. Besides being longer, the Sony FE 600mm F4 GM also has a larger diameter of 164mm compared to the Sigma 105mm F1.4 DG HSM's 116mm 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 105mm F1.4 DG HSM weighs 1645g, 45% (1395g) lighter than the Sony FE 600mm F4 GM's weight of 3040g.
Filter Threads
The Sony FE 600mm F4 GM has a filter size of 41mm whereas the Sigma 105mm F1.4 DG HSM has a 105mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 41mm filters that we recommend you to consider for the Sony FE 600mm F4 GM:
And these are the 105mm filters that we recommend for the Sigma 105mm F1.4 DG HSM:
Lens Mounts
Both the Sony FE 600mm F4 GM and the Sigma 105mm F1.4 DG HSM has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A9 III, Sony A7C Mark II and Sony A7CR.
Sigma 105mm F1.4 DG HSM is also available in Canon EF , Nikon F (FX) and Sigma SA mounts.
Focal Range
Sony FE 600mm F4 GM is a prime lens with fixed focal lenght of 600mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
900mm.
On the other hand, the Sigma 105mm F1.4 DG HSM is a prime lens with fixed focal lenght of 105mm which has an effective (full-frame 35mm equivalent) focal range of 157.5mm when used on a 35mm FF format camera.