The new HD PENTAX D FA 150-450mm f/4.5-5.6 DC AW Lens pairs advanced optical and mechanical design elements with an extensive 225-675mm-equivalent focal length range when you used on APS-C cameras.
The build quality of this lens is very good indeed, along with a combination of metal and high-quality plastics used for the construction and the bayonet being made of metal. It also sports a dust and moisture-resistant construction and weighs 2kg. As a result, it balances fairly well with the Pentax K-3 body used for testing.
It features the PENTAX-original, high-grade HD Coating to produce extra-sharp and high-contrast images even under demanding lighting conditions such as in backlight. It also incorporates three ED (Extra-low Dispersion) Glass elements, an Anomalous Dispersion Glass element to effectively compensate chromatic aberration. Its dustproof and weather-resistant body also makes it extremely dependable and durable in demanding outdoor conditions.
Additionally, this zoom lens is also equipped with the Pentax-developed Quick-Shift Focus System, which allows users to instantly switch to manual-focus operation after subject is captured in focus by the camera’s AF system. In order to improve its operability, a 3-position switch has been installed on this lens, allowing instant switching among QFS/A, QFS/M and MF modes. QFS/A is an autofocus-priority mode, that allows the user to switch to manual-focusing operation when autofocus operation is complete. The QFS/M is a manual-focus-priority mode, which enables the user to switch to manual focusing at any time — even when the AF system is in operation.
A lock button can be engaged to hold the zoom position in place while transporting the lens and a removable, rotating tripod collar is included with the lens for better balance when shooting atop a tripod.