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 DA 20-40mm F2.8-4 ED DC WR 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 DA 20-40mm F2.8-4 ED DC WR is the longer of the two lenses at 69mm. The Pentax DA 55mm F1.4 SDM with a length of 66mm, is 3mm shorter. Besides being longer, the Pentax DA 20-40mm F2.8-4 ED DC WR also has a larger diameter of 71mm 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 20-40mm F2.8-4 ED DC WR weighs 283g, 24% (92g) lighter than the Pentax DA 55mm F1.4 SDM's weight of 375g.
Filter Threads
The Pentax DA 55mm F1.4 SDM has a filter size of 58mm whereas the Pentax DA 20-40mm F2.8-4 ED DC WR 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 58mm filters that we recommend you to consider for the Pentax DA 55mm F1.4 SDM:
And these are the 55mm filters that we recommend for the Pentax DA 20-40mm F2.8-4 ED DC WR:
Lens Mounts
Both the Pentax DA 55mm F1.4 SDM and the Pentax DA 20-40mm F2.8-4 ED DC WR 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 DA 20-40mm F2.8-4 ED DC WR has a focal range of 20-40mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 30-60mm when used on a APS-C / DX format camera.
