The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 18-200mm f3.5-6.3 XR II LD and the Pentax 15mm F4 L 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. Tamron AF 18-200mm f3.5-6.3 XR II LD is the longer of the two lenses at 84mm. The Pentax 15mm F4 L with a length of 40mm, is 44mm shorter. Besides being longer, the Tamron AF 18-200mm f3.5-6.3 XR II LD also has a larger diameter of 74mm compared to the Pentax 15mm F4 L's 63mm 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 15mm F4 L weighs 212g, 46% (186g) lighter than the Tamron AF 18-200mm f3.5-6.3 XR II LD's weight of 398g.
Filter Threads
The Tamron AF 18-200mm f3.5-6.3 XR II LD has a filter size of 62mm whereas the Pentax 15mm F4 L has a 49mm 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 Tamron AF 18-200mm f3.5-6.3 XR II LD:
And these are the 49mm filters that we recommend for the Pentax 15mm F4 L:
Lens Mounts
Both the Tamron AF 18-200mm f3.5-6.3 XR II LD and the Pentax 15mm F4 L 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.
Tamron AF 18-200mm f3.5-6.3 XR II LD is also available in the Canon EF , Nikon F (DX) and Sony Alpha mounts.
Focal Range
Tamron AF 18-200mm f3.5-6.3 XR II LD has a focal range of 18-200mm and
11.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-300mm when used on a APS-C / DX format camera.
On the other hand, the Pentax 15mm F4 L is a prime lens with fixed focal lenght of 15mm which has an effective (full-frame 35mm equivalent) focal range of 22.5mm when used on a APS-C / DX format camera.
