HD Pentax-D FA 150-450mm F4.5-5.6 (APS-C)
We rarely come across lenses that are built as tough as this one. The 150-450mm sports an all-metal barrel that really makes no compromises. Its durable, weather-sealed construction yields a base weight of 2000g (4.4lb) that increases to 2325g (5.1lb) with the hood and tripod mount. Along with a camera body such as the Pentax K-3, the rig can weigh as much as 3200g (7lb). We thus recommend the use of an appropriately-sized tripod. If your tripod is not rated for this kind of load, you may experience excessive vibrations that can easily lead to blurry images.
Weather sealing diagram
A host of rubber seals and gaskets protect the lens from dust and moisture, as denoted by the AW (All Weather) designation. Note that while you zoom, due to the presence of weather seals throughout, it is normal for air to flow out of gaps in the camera, such as the viewfinder or buttons.
In addition, the front element is coated with Pentax's SP (Super Protect) coating which repels dust to simplify cleaning.
The lens accepts standard lens filters through its 86mm front filter thread. This a somewhat unusual diameter that is not shared with any other current Pentax lenses.
All-metal barrel, lens mount with red weather seal
While testing the 150-450mm in the field, we did not experience any significant zoom creep. Since the telescoping part of the barrel is rather large, however, we cannot preclude the possibility of creep developing over time, especially at the long end of the zoom range. To reduce potential strain on the zoom mechanism, a zoom lock switch is available at 150mm.
An extensive array of AF buttons and switches is placed between the zoom ring and focusing ring. The tripod mount behind the focusing ring can be turned freely when loosened; soft click stops at placed at 90-degree intervals. Furthermore, it is possible to remove the tripod foot entirely. When the foot is removed, only a small stub remains.
All in all, this new Pentax zoom is nothing short of professional-grade when it comes to build quality. It is built like a tank and rivals only the best lenses, past and present.