Pentax DA 17-70mm f/4 SDM Lens Review

Testing a lens always comes with some variability: optics are precise instruments, and even among copies from a top manufacturer like Pentax there will be better and worse performing samples. Beyond the technical, even, how much a particular lens's look appeals to you � and how much its flaws limit you � will depend heavily on what your needs and preferences are.

With excellent contrast, nice color handling, and improved CA control, the 17-70mm is capable of superior shots, especially in the context of landscape shooting. Several days of intense outdoor shooting with the 17-70mm, and the very pleasing shots that resulted, are a testament to just how good this optic can be. Compromised sharpness throughout at wider apertures will be a sticking point for some, which is a shame really: for certain kinds of shooting, the 17-70mm works quite well.

Given just how good Pentax's current-generation 18-55mm kit lens is, however, a bigger concern may be whether the 17-70mm's $600 price tag makes it a worthwhile upgrade. The more expensive lens buys you a little bit of speed at the telephoto end, and a little bit of range; when sharpness is firing on all cylinders at narrower apertures, there's simply no comparison between the two. The concern, though, is that for lots of general, walk-around shooting (which implies, at least, the lack of a tripod, and thus makes narrower apertures a challenge depending on light), it may be hard to realize the benefits of the more expensive glass.

The 17-70mm should appeal to architectural and nature photographers without question, and might even serve well as an urban shooting or general purpose lens, but even with all of the progress that Pentax has made in this series to improve build quality and correct wide-open aberrations, the adherence to a slow-at-the-wide-end f/4 constant aperture and nagging questions about sharpness leave us feeling a bit tossed up about the 17-70mm at the end of the day.

David Rasnake

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