The type of photography that you are planning to use is an important decision factor. Here we have evaluated the PENTAX28-105mm F3.5-5.6 WR and the Pentax DA 18-50mm F4.5-5.6 DC WR RE 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. PENTAX28-105mm F3.5-5.6 WR is the longer of the two lenses at 87mm. The Pentax DA 18-50mm F4.5-5.6 DC WR RE with a length of 71mm, is 16mm shorter. Besides being longer, the PENTAX28-105mm F3.5-5.6 WR also has a larger diameter of 73mm compared to the Pentax DA 18-50mm F4.5-5.6 DC WR RE's 41mm 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 18-50mm F4.5-5.6 DC WR RE weighs 158g, 64% (282g) lighter than the PENTAX28-105mm F3.5-5.6 WR's weight of 440g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Pentax KAF3 Mount for size comparison purposes.
Standard Lenses in Pentax KAF3 Mount for Size Comparison
Filter Threads
The PENTAX28-105mm F3.5-5.6 WR has a filter size of 62mm whereas the Pentax DA 18-50mm F4.5-5.6 DC WR RE 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 62mm filters that we recommend you to consider for the PENTAX28-105mm F3.5-5.6 WR:
And these are the 58mm filters that we recommend for the Pentax DA 18-50mm F4.5-5.6 DC WR RE:
Lens Mounts
Both the PENTAX28-105mm F3.5-5.6 WR and the Pentax DA 18-50mm F4.5-5.6 DC WR RE 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.
Focal Range
PENTAX28-105mm F3.5-5.6 WR has a focal range of 28-105mm and
3.8X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
42 - 157.5mm.
On the other hand, the Pentax DA 18-50mm F4.5-5.6 DC WR RE has a focal range of 18-50mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-75mm when used on a APS-C / DX format camera.
