The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax D FA 150-450mm F4.5-5.6 ED DC AW and the Tamron AF 18-250mm f3.5-6.3 II LD 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 D FA 150-450mm F4.5-5.6 ED DC AW is the longer of the two lenses at 242mm. The Tamron AF 18-250mm f3.5-6.3 II LD with a length of 84mm, is 158mm shorter. Besides being longer, the Pentax D FA 150-450mm F4.5-5.6 ED DC AW also has a larger diameter of 95mm compared to the Tamron AF 18-250mm f3.5-6.3 II LD's 74mm 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. Tamron AF 18-250mm f3.5-6.3 II LD weighs 430g, 78% (1570g) lighter than the Pentax D FA 150-450mm F4.5-5.6 ED DC AW's weight of 2000g.
Filter Threads
The Pentax D FA 150-450mm F4.5-5.6 ED DC AW has a filter size of 86mm whereas the Tamron AF 18-250mm f3.5-6.3 II LD 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 86mm filters that we recommend you to consider for the Pentax D FA 150-450mm F4.5-5.6 ED DC AW:
And these are the 62mm filters that we recommend for the Tamron AF 18-250mm f3.5-6.3 II LD:
Lens Mounts
The Pentax D FA 150-450mm F4.5-5.6 ED DC AW has the Pentax KAF3 lens mount whereas the Tamron AF 18-250mm f3.5-6.3 II LD has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF3 Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Tamron AF 18-250mm f3.5-6.3 II LD is also available in Canon EF , Nikon F (DX) and Sony Alpha mounts.
Focal Range
Pentax D FA 150-450mm F4.5-5.6 ED DC AW has a focal range of 150-450mm and
3.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
225 - 675mm.
On the other hand, the Tamron AF 18-250mm f3.5-6.3 II LD has a focal range of 18-250mm and 13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-375mm when used on a APS-C / DX format camera.
