Pentax’s 18-250mm f/3.5-6.3 DA smc is compatible with its entire series of APS-C format digital SLRs. Mounted to a model such as a K-m, K-x or K-7, the Pentax 18-250mm F/3.5-6.3 DA SMC offers a 14x zoom ratio and a focal length that’s equivalent to 27-375mm in film terms. Featuring a hard-wearing metal lens mount and zoom lock to prevent lens creep, first impressions were good and are backed up with a large zoom ring that operates smoothly throughout the entire focal length.
Unfortunately, the focus ring doesn’t quite hit the same mark; without an AF/MF switch on the lens barrel, you’re dependent on selecting the focus type from the body of the camera, which is not ideal in fast-paced shooting situations. Also, with MF selected, the zoom ring is noisy when it’s used manually.
Unlike other optics in the Pentax lens range, the 18-250mm doesn’t offer a Supersonic Drive Motor (SDM) and the result is noisy AF operation and a slightly sluggish performance that’s highly noticeable when AF is set to Continuous.
Optically, it features aspherical (AL) and extra-low-dispersion (ED) elements and an internal focusing system to prevent the front element rotating when focusing. Image stabilisation is not featured on this lens, as all current Pentax D-SLRs feature Shake Reduction systems in the camera body to keep images sharp. At the front end, it uses a 62mm thread and a good lens hood is also thrown in for the £349 price.
AT A GLANCEPrice: £349
Mount: Pentax K-AF
Construction: 16 elements in 13 groups
Aperture blades: 7
Max aperture: Wide f/3.5, tele f/5.6
Min aperture: f/22-45
Minimum focus: 45cm
Filter size: 62mm
Dimensions (DxL): 75x85.5mm
Weight: 455g
www.pentax.co.uk