Pentax K-5 Review - Performance

Generally excellent performance for a prosumer SLR.

Startup/Shutdown
Power on to first shot	~0.6 second	Time it takes for camera to turn on and take a shot.
Shutdown	~0.2 second	How long it takes to turn off.
Buffer clearing time	23 seconds* after 31 L/P JPEGs	Worst case buffer clearing time. -- This is the delay after a set of shots before you can remove the card. Some cameras won't shut down until the buffer is cleared. See Cycle-Time table below for more buffer clearing times.
	32 seconds* after 23 RAW frames
	44 seconds* after 22 RAW + L/P JPEGs
* Note: Buffer clearing times measured with a SanDisk Extreme III 30MB/sec 8GB SDHC card. Slower cards will produce correspondingly slower clearing times. Slow cards may also limit length of bursts in continuous mode. ISO sensitivity and noise reduction settings can also affect cycle times and burst mode performance.

Startup and shutdown times were about average for a prosumer SLR. (Sensor cleaning at startup is enabled by default.) Buffer clearing times were a little slow for the class of camera, but no surprise given the K-5's large files, deep buffers and the use of SD cards. (The Pentax K-5 doesn't take advantage of increased performance offered by the new higher-speed UHS-I compliant cards.)

Mode Switching
Play to Record, first shot	~0.3 second	Time until first shot is captured.
Record to Play	~2.0 seconds	Time to display a large/premium JPEG file immediately after capture.
Display recorded image	~0.2 second	Time to display a large/premium JPEG file already on the memory card.

Play to Record was very fast as was displaying a recorded image, but switching from Record to Play was somewhat sluggish.

Shutter Response (Lag Time)
Full Autofocus Single Area (center) AF	0.104 second		Time from fully pressing shutter button to image capture. (All AF timing measurements taken with Sigma 70mm f/2.8 prime, unless otherwise noted.)
Full Autofocus Auto Area (11-points) AF	0.118 second		Time from fully pressing shutter button to image capture.
Full Autofocus Single Area AF, Flash enabled	0.206 second		Time from fully pressing shutter button to image capture. Auto Flash enabled.
Pre-focused	0.092 second		Time to capture, after half-pressing and holding shutter button.
Continuous AF	0.093 second		This mode is release priority so subject may be out of focus; we have no way to measure performance with moving subjects.
Manual focus	0.092 second		For most cameras, shutter lag is less in manual focus than autofocus, but usually not as fast as when the camera is "pre-focused."
Live View
Firmware version	1.01	1.02
Full Autofocus (Phase-Detect AF) Live View mode	1.34 seconds	1.30 seconds	Time from fully pressing shutter button to image capture with Sigma 70mm f/2.8 prime or Pentax 17-70mm f/4 SDM zoom.
Full Autofocus (Contrast-Detect AF) Live View mode	1.27 seconds	1.25 seconds	Time from fully pressing shutter button to image capture with Sigma 70mm f/2.8 prime or Pentax 17-70mm f/4 SDM zoom.
Pre-focused Live View mode	0.384 second	0.384 second	Time to capture, after half-pressing and holding shutter button.

The shutter lag numbers above measure time from shutter button press to image capture, with the lens already set to the correct focal distance. This largely removes the issue of differences in lens focusing speed, and measures how fast the camera can measure and act on focus information. In this metric, the Pentax K-5 was faster than average for a prosumer SLR. The K-5 required only 0.104 second for full AF when using Single-point (center) AF mode (our default full AF lag test). This increased only slightly to 0.118 second in Auto area AF mode, which is still very fast. When prefocused, shutter lag was 0.092 second which while fast, isn't quite as fast as some competing models. Continuous and Manual focus lag times were 0.093 and 0.092 second respectively.

As expected, the Pentax K-5's Live View mode was much slower to focus. Using firmware 1.01, full autofocus shutter lag was approximately 1.34 seconds using phase-detect AF mode. This decreased slightly to approximately 1.27 seconds using contrast-detect AF mode. We also tested Live View AF with a Pentax 17-70mm f/4 AL SDM lens at 70mm, but full AF lag times weren't much different than with the Sigma 70mm lens. We noticed some interesting behavior in Live View mode, though: the Pentax K-5 will take a shot unfocused, even with the default Focus-priority set as the release mode, so that's something you'll need to be aware of. We needed to half-press the shutter release long enough for focusing to begin before fully depressing for a focused shot, even in phase-detect AF mode. Waiting for focus confirmation before fully depressing the shutter release raised the total lag to about 1.6 seconds. This behavior seems intentional as the K-5 user manual says to half-press for focus first, but we found it unusual especially for phase-detect AF mode. Prefocused shutter lag was pretty fast for Live View mode, though, at 0.384 second.

Firmware Update. Live View autofocus speeds improved only slightly after updating firmware to 1.02. Phase-detect AF lag dropped from 1.34s to 1.30s, and contrast-detect AF lag dropped from 1.27s to 1.25s. The firmware had no effect on prefocused shutter lag, or on AF speeds when using the optical viewfinder. A bigger improvement with the new firmware was the behavior during Live View focusing. We no longer had to first half-press the shutter release and wait for focusing to begin before fully depressing to get a focused shot. Fully depressing the shutter in one quick motion resulted in focused images after the upgrade. However, if the previous image was still being written to the SD card when the shutter release was fully depressed, the Pentax K-5 would shoot without attempting to refocus.

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.

Cycle Time (shot-to-shot)
Single Shot mode Large/Premium JPEG	0.27 second 12 seconds to clear	Time per shot, averaged over 20 shots, with no signs of slowing down.
Single Shot mode RAW	0.26 second 30 seconds to clear	Time per shot, averaged over 20 shots, with no signs of slowing down.
Single Shot mode RAW + L/P JPEG	0.26 second 46 seconds to clear	Time per shot, averaged over 21 shots (buffer depth).
Early shutter penalty?	No	Some cameras refuse to snap another shot if you release and press the shutter too quickly in Single Shot mode, making "No" the preferred answer.
Continuous mode Large/Premium JPEG	0.15 second (6.48 fps); 31 frames total; 23 seconds to clear^*	Time per shot, averaged over the buffer length of 31 shots, then slows to an average of 0.61 second (1.63 fps) for subsequent shots, with a huge amount of variation (>800%) in cycle times when buffer is full.
Continuous mode RAW	0.16 second (6.45 fps); 23 frames total; 32 seconds to clear^*	Time per shot, averaged over the buffer length of 23 frames, then slows to an average of 1.25 seconds (0.80 fps) for subsequent shots, with about 400% variation in cycle times when buffer is full.
Continuous mode RAW + L/P JPEG	0.16 second (6.44 fps); 22 frames total; 44 seconds to clear^*	Time per shot, averaged over the buffer length of 22 frames, then slows to an average of 2.22 seconds (0.45 fps) for subsequent shots, with about 31% variation in cycle times when buffer is full.
Flash recycling	2.2 seconds	Flash at maximum output.
* Note: Buffer clearing times measured with a SanDisk Extreme III 30MB/sec 8GB SDHC card. Slower cards will produce correspondingly slower clearing times. Slow cards may also limit length of bursts in continuous mode. ISO sensitivity and noise reduction settings can also affect cycle times and burst mode performance.

Shot-to-shot cycle times were very fast, at 0.27 second for Large/Premium JPEG and 0.26 seconds for DNG or DNG + L/P JPEG files.

Continuous mode was very good for a prosumer SLR, at about 6.5 frames per second for L/P JPEGs or DNG files, and about 6.4 frames per second for DNG + L/P JPEG files. That's a little slower than Pentax's rating of 7 frames per second, but still very good.

The Pentax K-5's buffer depths were also quite good for a prosumer SLR, considering the burst rates and file sizes. The K-5 managed 31 L/P JPEGs, 23 DNGs and 22 DNG + L/P JPEG frames before slowing down. (You'll likely do better, as the target image we use for our tests is designed to be difficult to compress.)

The Pentax K-5's flash took 2.2 seconds to recharge after a full-power shot, which is also quite fast.

Note that K-5 firmware version 1.01 was used for these tests, which improves buffer performance significantly over firmware 1.00. You can download the latest firmware here.

Download speed
Windows Computer, USB 2.0	11,491 KBytes/sec	Typical Values: Less than 600=USB 1.1; 600-769=USB 2.0 Low; Above 770=USB 2.0 High

Connected to a computer or printer with USB 2.0, downloads are very fast.

Bottom line, the Pentax K-5's performance was generally excellent. Autofocus speeds were very fast, and continuous mode speeds were also fast. Mode switching from Record to Play was sluggish, but that's not a serious issue since you won't lose any shots waiting to switch to Play mode. The time-critical Play to Record delay was very fast. Buffer clearing times were a bit of a disappointment, limited by its SD card interface and relatively large files. Still, buffer depths were quite good, so you likely won't lose too many shots unless you need to take long bursts back-to-back.

Battery
Average battery life for a semi-professional model SLR.

Operating Mode	Number of Shots
Optical Viewfinder, (CIPA standard)	740
Live View LCD, (CIPA standard)	Unknown

The Pentax K-5 uses a custom rechargeable lithium-ion battery for power, and ships with a charger. Battery life is about average for a semi-pro model (much better than average compared to most consumer models), but if you plan to use Live View or shoot movies much, you'll definitely want to have a spare battery to bring along.

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-5 accepts SD/SDHC memory cards as well as the newer SDXC type with the latest firmware. No card is included with the camera. Pentax doesn't seem to specify a minimum speed grade, but we recommend cards with at least SD Class 6 speed rating if you want to shoot HD movies.

Image Capacity vs Resolution/Quality 2GB Memory Card		Premium	Best	Better	Good	RAW (14-bit PEF or DNG)
4,928 x 3,264	Images (Avg size)	134 15.3 MB	214 9.6 MB	379 5.4 MB	749 2.7 MB	58 35.3 MB
4,928 x 3,264	Approx. Comp.	3:1	5:1	9:1	18:1	0.8:1
3,936 x 2,624	Images (Avg size)	208 9.8 MB	332 6.2 MB	585 3.5 MB	1,138 1.8 MB	-
3,936 x 2,624	Approx. Comp.	3:1	5:1	9:1	17:1	-
3,072 x 2,048	Images (Avg size)	339 6.0 MB	543 3.8 MB	945 2.2 MB	1,807 1.1 MB	-
3,072 x 2,048	Approx. Comp.	3:1	5:1	9:1	17:1	-
1,728 x 1,152	Images (Avg size)	1,041 1.9 MB	1,617 1.3 MB	2,793 733 KB	5,121 400 KB	-
1,728 x 1,152	Approx. Comp.	3:1	5:1	8:1	15:1	-

In the table above, image capacity and sizes are approximate and will vary according to the complexity of the scene and other factors. We strongly recommend buying a large, fast SDHC card. You should probably consider at least an 8GB card if not a 16GB one, to give yourself extra space for extended outings, especially if you plan on doing a lot of RAW or HD movie shooting. (Check the shopping link above, cards are cheap these days, so there's no reason to skimp -- But do consider faster cards for this camera, to reduce buffer clearing times.)