The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax DA 55mm F1.4 SDM and the Pentax 17-70mm F4.0 AL SDM 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. Pentax 17-70mm F4.0 AL SDM is the longer of the two lenses at 94mm. The Pentax DA 55mm F1.4 SDM with a length of 66mm, is 28mm shorter. Besides being longer, the Pentax 17-70mm F4.0 AL SDM also has a larger diameter of 75mm compared to the Pentax DA 55mm F1.4 SDM's 70mm 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 DA 55mm F1.4 SDM weighs 375g, which means it is 110g (22%) lighter than the Pentax 17-70mm F4.0 AL SDM which has a weight of 485g.
Filter Threads
The Pentax DA 55mm F1.4 SDM has a filter size of 58mm whereas the Pentax 17-70mm F4.0 AL SDM has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the Pentax DA 55mm F1.4 SDM:
And these are the 67mm filters that we recommend for the Pentax 17-70mm F4.0 AL SDM:
Lens Mounts
Both the Pentax DA 55mm F1.4 SDM and the Pentax 17-70mm F4.0 AL SDM has the same Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with the Pentax KAF3 lenses are , and .
Focal Range
Pentax DA 55mm F1.4 SDM is a prime lens with fixed focal lenght of 55mm which has an effective (full-frame 35mm equivalent) focal range of
82.5mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 17-70mm F4.0 AL SDM has a focal range of 17-70mm and 4.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 25.5-105mm when used on a APS-C / DX format camera.
