Pentax K-S2 Performance

Good overall performance for its class.

The Pentax K-S2's startup time was a little slow for a DSLR, but switching from Play to Record and taking a shot was quite fast.

The Pentax K-S2's full autofocus shutter lag when shooting the same target multiple times was much faster than average for a consumer DSLR. The K-S2 required only 0.124 second for full AF using the center focus point with the kit lens at medium focal length. (We also tested this with our Sigma 70mm f/2.8 macro reference lens, and got identical results.) Enabling the flash raised shutter lag only slightly to 0.153 second, reflecting the added delay caused by the metering preflash. Manual focus shutter lag was even faster than autofocus as expected, at 0.098 second. When prefocused, shutter lag dropped further to 0.077 second which is about average for a consumer DSLR.

As expected, full autofocus lag was slower in Live View mode. The Pentax K-S2 took about 0.75 second to focus in Live View in our tests. That's noticeably slower than using the optical viewfinder, but actually not bad for a DSLR. (How fast the lens can adjust focus makes a big difference here.) When prefocused, shutter lag fell to a more snappy 0.214 second in 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.

Shot-to-shot cycle times were quite good for a consumer DSLR, at 0.35 second for Large Best Quality JPEGs or RAW + L/B JPEG frames. (Note that fast single-shot times like these depend a lot on the tester's rhythm, so your results may vary.) We no longer test just RAW files in single-shot mode, as it's usually somewhere in between JPEG and RAW+JPEG cycle time.

Continuous H mode speed was decent at about 5.2 frames per second regardless of file type, very close to Pentax's 5.5 fps spec. Note that the K-S2 captures 12-bit RAW files in Pentax PEF or Adobe DNG format, and no compression options are given for RAW files. There is also a Continuous L mode rated at 3 frames per second, but we did not test that mode.

Buffer depth in continuous mode was good when shooting just JPEGs at 28 Large Best Quality JPEG frames before the camera slowed, though with RAW files buffer depths were somewhat shallow at 9 RAW frames or 6 RAW+L/B JPEG frames. This is typical of DSLRs in its price range, though. Also note that our test target was designed to be difficult to compress, so shooting typical subjects may yield deeper buffers.

Buffer clearing was reasonable with our fast UHS-I SDHC card, taking 8 seconds to clear after a max-length burst of frames in all three format modes.

The K-S2's built-in flash took an average of 2.3 seconds to recharge after full-power shots, which is quite fast.

Bottom line, the Pentax K-S2's performance was generally good for its class in our tests. Startup was a little slow for a DSLR, but AF speeds were very fast, and shutter lag, single shot cycle-times, burst speeds and flash recycle times were all good. Buffer depths with RAW files were somewhat shallow, but that's not unusual for its class.

Battery Life
Poor battery life for a DSLR.

The Pentax K-S2 uses a custom rechargeable D-LI109 lithium-ion battery for power, and ships with a dedicated charger. Battery life when using the optical viewfinder is well below average for a DSLR, and Pentax does not specify battery life for Live View mode, which will certainly be a lot lower. We strongly recommend you pick up a spare battery and keep it freshly charged and on-hand for extended outings.

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))