The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 500mm F4.5 EX DG HSM and the Pentax 55-300mm F4.0-5.8 ED 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 500mm F4.5 EX DG HSM is the longer of the two lenses at 350mm. The Pentax 55-300mm F4.0-5.8 ED with a length of 112mm, is 238mm shorter. Besides being longer, the Sigma 500mm F4.5 EX DG HSM also has a larger diameter of 123mm compared to the Pentax 55-300mm F4.0-5.8 ED's 71mm 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. Pentax 55-300mm F4.0-5.8 ED weighs 440g, 86% (2710g) lighter than the Sigma 500mm F4.5 EX DG HSM's weight of 3150g.
Filter Threads
The Sigma 500mm F4.5 EX DG HSM has a filter size of 46mm whereas the Pentax 55-300mm F4.0-5.8 ED has a 58mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 46mm filters that we recommend you to consider for the Sigma 500mm F4.5 EX DG HSM:
And these are the 58mm filters that we recommend for the Pentax 55-300mm F4.0-5.8 ED:
Lens Mounts
Both the Sigma 500mm F4.5 EX DG HSM and the Pentax 55-300mm F4.0-5.8 ED has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III.
Sigma 500mm F4.5 EX DG HSM is also available in the Canon EF , Nikon F (FX) and Sigma SA mounts.
Focal Range
Sigma 500mm F4.5 EX DG HSM is a prime lens with fixed focal lenght of 500mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
750mm.
On the other hand, the Pentax 55-300mm F4.0-5.8 ED has a focal range of 55-300mm and 5.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 82.5-450mm when used on a APS-C / DX format camera.
