The SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM is a lens praised by many Pentax DSLR shooters. Having been launched in early 2007, it was the first "star" lens to join the Pentax DA (digital-only) lineup. Pentax uses the star symbol to denote their professional lenses, and such lenses generally boast premium image quality and fast, fixed apertures. The DA* 50-135mm is no exception to this rule.
As a DA* lens, the 50-135mm also features silent SDM autofocus and full weather-sealing, meaning that it's safe to shoot with this lens in adverse weather (though dunking it in your pool will probably not end well). Even though all Pentax DSLRs made after this lens was launched support SDM, the 50-135mm will also work with the traditional screwdrive AF system on older cameras, such as the K100D or *ist D series.
This lens corresponds roughly to the popular 70-200mm focal length on full-frame, giving it short- to medium-telephoto capabilities. Pentax also offers a DA* 60-250mm F4 lens for those who want even more reach.
Interestingly, this lens features both internal focusing and internal zooming, meaning that it does not extend at all during use. This design is typical of lenses in its class: the current 70-200mm lenses from Canon and Nikon are also like this.
Specifications aside, what we really want to focus on in this review is image quality. Is the optical performance of this lens worth the investment? For what purposes does this lens shine? Read on to find out!
Review originally published on February 16th, 2013