The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax 16-85mm F3.5-5.6 ED DC WR and the Pentax 18-135mm F3.5-5.6ED 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 16-85mm F3.5-5.6 ED DC WR is the longer of the two lenses at 94mm. The Pentax 18-135mm F3.5-5.6ED with a length of 76mm, is 18mm shorter. Besides being longer, the Pentax 16-85mm F3.5-5.6 ED DC WR also has a larger diameter of 78mm compared to the Pentax 18-135mm F3.5-5.6ED's 73mm 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 18-135mm F3.5-5.6ED weighs 405g, 17% (83g) lighter than the Pentax 16-85mm F3.5-5.6 ED DC WR's weight of 488g.
Filter Threads
The Pentax 16-85mm F3.5-5.6 ED DC WR has a filter size of 72mm whereas the Pentax 18-135mm F3.5-5.6ED has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 72mm filters that we recommend you to consider for the Pentax 16-85mm F3.5-5.6 ED DC WR:
And these are the 62mm filters that we recommend for the Pentax 18-135mm F3.5-5.6ED:
Lens Mounts
Both the Pentax 16-85mm F3.5-5.6 ED DC WR and the Pentax 18-135mm F3.5-5.6ED 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
Pentax 16-85mm F3.5-5.6 ED DC WR has a focal range of 16-85mm and
5.3X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
24-127.5mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 18-135mm F3.5-5.6ED has a focal range of 18-135mm and 7.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-202.5mm when used on a APS-C / DX format camera.
