Pentax K5 vs Sony SLT Alpha 55 — Which Is Better?

The Pentax K5 and the Sony SLT Alpha 55 are both DSLRs announced within a month of each other in 2010, so this comparison comes down to how each body balances size against capability. The K5 is the larger build at 131 x 97 x 73 mm and 740 g. The Alpha 55 is a lighter body at 500 g, a 240 g saving, and measures 124 x 92 x 85 mm.

The Alpha 55 is the better pick for burst shooting of moving subjects, offering 10 fps against 7 fps from the K5, plus 15 autofocus points against 11. The K5 counters with a shorter maximum exposure of 1/8000 second against 1/4000, which helps keep wide apertures usable in bright daylight.

For framing, they differ in viewfinder design: the K5 uses an optical pentaprism, while the Alpha 55 uses an electronic viewfinder with 1150000 dots. Resolution barely differs, at 16.3 megapixels against 16.2, so neither body offers a real cropping advantage. Both use APS-C CMOS sensors with in-body stabilisation, which means any Pentax KAF2 or Sony Alpha DT lens you mount gains shake reduction.

For video, the Alpha 55 is the stronger choice: its maximum frame rate of 30 fps against the K5's 25 gives smoother motion in moving scenes. It also records in AVCHD or MP4 rather than the K5's Motion JPEG, which gives you more file-format options when you edit.

The K5 keeps one video trick: it offers a built-in interval timer for timelapse sequences, which the Alpha 55 does not. Both cameras share the same Full HD resolution ceiling.

The K5 is the camera to take out in poor weather, with weather sealing that the Alpha 55 lacks. That protection matters for landscape shoots in drizzle or dusty trails, where the Sony would need a cover.

The Alpha 55 answers with two conveniences the K5 does not offer: a flip screen for framing at awkward angles, and built-in GPS to geotag travel and wildlife photos. Their rear screens match on size and detail, with both using 3 inch displays of 921000 dots and live view.

The K5 leads on battery endurance, rated for 980 shots per charge against 380 for the Alpha 55. That rating favours it for full days of shooting away from a charger.

For cards, the difference is flexibility: both accept SD, SDHC and SDXC media, but the Alpha 55 also accepts Memory Stick Pro Duo and Pro-HG Duo. Neither camera offers dual card slots or USB charging.