The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 120-400mm F4.5-5.6 DG HSM and the Sigma 150-500mm F5-6.3 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 150-500mm F5-6.3 is the longer of the two lenses at 252mm. The Sigma 120-400mm F4.5-5.6 DG HSM with a length of 203mm, is 49mm shorter. Besides being longer, the Sigma 150-500mm F5-6.3 also has a larger diameter of 95mm compared to the Sigma 120-400mm F4.5-5.6 DG HSM's 92mm 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 120-400mm F4.5-5.6 DG HSM weighs 1640g, which means it is 140g (7%) lighter than the Sigma 150-500mm F5-6.3 which has a weight of 1780g.
Below you can find the dimension and weight table of the Telephoto Zoom Lenses in Pentax KAF3 Mount for size comparison purposes.
Super Telephoto Lenses in Pentax KAF3 Mount for Size Comparison
Filter Threads
The Sigma 120-400mm F4.5-5.6 DG HSM has a filter size of 77mm whereas the Sigma 150-500mm F5-6.3 has a 86mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Sigma 120-400mm F4.5-5.6 DG HSM:
And these are the 86mm filters that we recommend for the Sigma 150-500mm F5-6.3:
Lens Mounts
Both the Sigma 120-400mm F4.5-5.6 DG HSM and the Sigma 150-500mm F5-6.3 has the same Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with the Pentax KAF3 lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Sigma 120-400mm F4.5-5.6 DG HSM is also available in the Sony Alpha mount.
Sigma 150-500mm F5-6.3 is also available in Canon EF , Nikon F (FX), Sony Alpha and Sigma SA mounts.
Focal Range
Sigma 120-400mm F4.5-5.6 DG HSM has a focal range of 120-400mm and
3.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
180 - 600mm.
On the other hand, the Sigma 150-500mm F5-6.3 has a focal range of 150-500mm and 3.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 225 - 750mm.
