The Tamron SP AF 17-50mm f/2.8 XR Di II (model A16M) is a fast aperture medium zoom range lens for Pentax DSLR Cameras (with APS-C sized sensors). The lens is part of Tamron's Di II (Digitally Integrated Design II) line of lenses. Di II lenses have optics designed specifically for the unique challenges and performance characteristics of 24x16mm sized digital sensors such as increased pixel density and sensor reflectivity. The 17-50mm offers a great general purpose zoom range spanning from moderately wide angle at the 17mm focal length to the start of the portrait lens range at it's 50mm focal length.
The f/2.8 maximum aperture is constant throughout full the zoom range, makes shooting in challenging available lighting conditions possible, and allows significant background blur. Bright f/2.8 aperture zooms like this one are the go-to general purpose choice of most working professional photographers. Tamron has been an industry leader in engineering high performance lenses that are more compact than traditional designs and the 17-50 benefits from that expertise. Tamron engineers have adeptly included three XR (Extra Refractive Index) elements, two Hybrid Aspherical elements, and an LD (Low Dispersion) glass element in the optical arrangement which delivers high image quality without the size and weight penalty of more traditional designs. The SP AF 17-50mm f/2.8 XR Di II weighs-in at a relatively light 440g (15.5oz) and uses 67mm filters.
The Tamron 17-50mm f/2.8 XR Di II is a superb versatile all purpose lens and it travels well thanks to it's excellent form factor. It's a great option for Pentax DSLR users wanting high quality images and flexibility without being weighed down unnecessarily.
- Superior Performance medium zoom range lens
- Designed exclusively for 24x16mm size sensors
- For Pentax KA2-Mount
- Versatile zoom goes from wide angle to the start of the portrait range
- Di II (Digitally Integrated Design II) optics optimized for higher pixel density and sensor reflectance
- Bright f/2.8 constant maximum aperture
- Compact form factor
- 3 XR (Extra Refractive Index) elements
- 2 Hybrid Aspherical lens elements
- 1 LD (Low Dispersion) glass element
- Circular aperture diaphragm (7 blades)
- Gear drive focus (uses camera AF motor)
- IF (Internal Focus) design and non-rotating filter ring
- Close focus to 0.27m (10.6in)
- Zoom lock switch prevents barrel extension while carrying
- Weighs only 440g (15.5oz)
- Uses 67mm filters
Available accessories include the DA09 petal style bayonet lens hood and 67mm filters.