Pentax K-r Performance

Generally excellent performance for an entry-level consumer digital SLR.

The Pentax K-r's startup and shutdown times were quite good for a consumer SLR. Buffer clearing times were a bit sluggish, but understandable given the relatively deep buffer depths.

Play to Record mode delay was very good for a consumer SLR, though switching from Record to Play was quite sluggish.

Full autofocus shutter lag using single-point (center) AF mode was excellent, at 0.105 second with our reference Sigma 70mm f/2.8 lens. Switching to auto-area AF mode increased lag slightly to 0.118 second, but that's still very fast for a consumer model. Enabling the flash increased the lag to 0.153 second, which is still very fast. Pre-focused shutter lag was good, at 0.097 second (pre-focused means half-pressing and holding down the shutter button before the final exposure). Continuous autofocus lag and Manual focus lag weren't much slower than prefocused, at 0.099 and 0.098 second respectively.

As expected, Live View mode shutter lag was a lot slower than using the optical viewfinder. Using phase-detect mode, full autofocus lag averaged about 1.2 seconds with our Sigma 70mm f/2.8 reference lens. That reduced to about a second when using contrast-detect mode. That's a little unusual as phase-detect AF is usually faster, but we don't change subject distance between iterations of our test, so the lens doesn't have to refocus much for contrast-detect mode, and the extra mirror flip required by phase-detect does take time. Prefocused, Live View mode shutter lag was 0.335 second, which is not bad for Live View mode.

To minimize the effect of different lens' focusing speed, we test AF-active shutter lag with the lens already set to the correct focal distance. We also use the same Sigma 70mm f/2.8 macro with every camera (on all platforms except Four Thirds/Micro Four Thirds and Nikon consumer models lacking an in-body focus motor), to further reduce variation, and because our tests showed that focus-determination time with this lens was close to the fastest, across multiple camera bodies from different manufacturers. Being an older design with a non-ultrasonic motor, it wouldn't be the fastest at slewing from one focus setting to another, but that's exactly the reason we measure focus determination speed, which is primarily a function of the camera body, vs focus adjustment speed, which is primarily a function of the lens.

Shot-to-shot cycle times were very good for a consumer SLR, at about 0.31 second for JPEG or RAW files, and oddly, even faster at 0.27 second for RAW + L/F JPEG files. Continuous speeds were excellent for an entry-level consumer model, ranging from about 5.6 to 5.7 frames per second depending on the image file type in Continuous Hi mode. That's not quite as fast as Pentax's six frames per second specification, but still excellent nonetheless. A Continuous Lo speed is rated by Pentax at two fps, however we didn't test that mode.

Buffer depths were also very good for an entry-level model, at 30 Large/Fine JPEGs, 13 RAW and 10 RAW + L/F JPEG frames. (Note that our target image for this test is difficult to compress, so you'll likely get even longer JPEG bursts with more typical subjects.) The flash takes 2.0 seconds to recharge after a full-power shot, which is also very fast.

Connected to a computer or printer with USB 2.0, download speeds were very fast as well.

Bottom line, the Pentax K-r is very fast in just about every aspect of its operation. Continuous mode speeds are excellent, among the fastest in its class, and shutter lag and cycle times are quite fast, too. Buffer depths are also quite generous. All this means the Pentax K-r should do well in most shooting situations, including some sports.

Battery
Below average battery life for an SLR.

The Pentax K-r ships with a rechargeable Li-ion battery and charger, but can also use four AA-type batteries with an optional D-BH109 AA battery holder. Battery life is below average for an SLR using the optical viewfinder with either type of rechargeable battery, and will most certainly be much less when using the LCD in Live View mode. We strongly recommend you pick up a spare Lithium-ion battery pack (or the AA battery holder, a couple sets of rechargeable NiMH AA batteries and a good quality charger), for extended outings or if you plan to use Live View or shoot video a lot.

The table above shows the number of shots the camera is capable of (on either a fresh set of disposable batteries or a fully-charged rechargeable battery as appropriate), based on CIPA battery-life and/or manufacturer standard test conditions.

(Interested readers can find an English translation of the CIPA DC-002 standards document here. (180K PDF document))

Storage
The Pentax K-r accepts SD/SDHC memory cards and SDXC cards with firmware 1.01; no card is included with the camera. The Pentax K-r operating manual doesn't specify a minimum Speed Class for shooting HD video, but since the K-r uses relatively inefficient Motion JPEG encoding for movies, you'll need at least a Speed Class 6 card for recording best quality 720p movies.

We strongly recommend buying either a large capacity SDHC card, at least a 4GB card, preferably a 8-16GB one, to give yourself extra space for extended outings and video. (Check the shopping link above, cards are really cheap these days, so no reason to skimp.)