Pentax K-7 Review - Performance

Very good speed for a prosumer digital SLR.

Startup/Shutdown
Power on to first shot	0.6 second	Time it takes for camera to turn on and take a shot.
Shutdown	0.6 second	How long it takes to turn off.
Buffer clearing time	15 seconds * after 20 LSF 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.
	13 seconds * after 13 RAW files
	13 seconds * after 9 RAW + LSF JPEGs
*Note: Buffer clearing times measured with a SanDisk Extreme III 8GB SDHC memory card. Slower cards will produce correspondingly slower clearing times. Slow cards may also limit length of bursts in continuous mode. ISO sensitivity and other settings such as D-Range or NR can also affect cycle times and burst mode performance.

The Pentax K-7's startup and shutdown times are about average for an SLR. Buffer clearing time depends on the image size and quality, burst length and how fast the card is.

Mode Switching
Play to Record, first shot	0.1 second	Time until first shot is captured.
Record to Play	1.6 seconds	Time to display a large / superfine file immediately after capture.
Display recorded image	0.2 second	Time to display a large/fine file already on the memory card.

Mode switching time is good for an SLR, though switching from Record to Play was a bit on the slow side.

Shutter Response (Lag Time)
Optical Viewfinder
Full Autofocus, Single-Point AF (center point)	0.093 second	Time from fully pressing shutter button to image capture (with Sigma 70mm f/2.8 prime).
Full Autofocus, Auto-Area AF	0.108 second	Time from fully pressing shutter button to image capture (with Sigma 70mm f/2.8 prime).
Full Autofocus, Single-Point AF Flash enabled	0.148 second	Time from fully pressing shutter button to image capture, Auto Flash enabled (with Sigma 70mm f/2.8 prime).
Pre-focused	0.074 second	Time to capture, after half-pressing and holding shutter button.
Continuous AF	0.075 second	This mode usually shows no speed increase with our static subject; we have no way to measure performance with moving subjects.
Manual focus	0.075 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 Mode
Full Autofocus, Phase-Detect AF	1.2 seconds	Time from pressing the AF button and pressing shutter button to image capture (with Sigma 70mm f/2.8 prime).
Full Autofocus, Contrast-Detect AF	2.3 seconds	Time from pressing the AF button and pressing shutter button to image capture (with Sigma 70mm f/2.8 prime).
Full Autofocus, Contrast-Detect AF	4.8 seconds	Time from pressing the AF button and pressing shutter button to image capture (with Pentax 17-70mm f/4 SDM).
Pre-focused	0.405 second	Time to capture, after pressing and holding the AF button.

Full autofocus shutter lag using single-point (center) AF mode is excellent, at 0.093 second with our reference Sigma 70mm f/2.8 lens. Switching to auto-area AF mode increased lag slightly to 0.108 second, but that's very fast for a prosumer model. Enabling the flash added only about 0.055s delay, which is very good. "Pre-focus" time is also quite fast, at 0.074 second (pre-focusing 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, both at only 0.075 second.

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 increased to 2.3 seconds when using Contrast-Detect mode, ranging between 2.1 and 2.5 seconds. For good measure, we tried the Pentax 17-70mm f/4 lens, thinking the SDM focus motor may help, but it turned out to be even slower than the Sigma lens, at 4.8 seconds on average. It also varied much more than with the Sigma, ranging from 3.7 to 6.2 seconds. Prefocused, Live View mode shutter lag was a tolerable 0.405 second.

Cycle Time (shot-to-shot)
Single Shot mode Large SuperFine JPEG	0.24 second	Time per shot, averaged over 25 shots, 15 seconds to clear.
Single Shot mode RAW	0.26 second	Time per shot, averaged over 13 shots, 13 seconds to clear.
Single Shot mode RAW + LSF JPEG	0.24 second	Time per shot, averaged over 8 shots, 15 seconds to clear.
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 Lo Large SuperFine JPEG	0.33 second (3.03 frames per second); 33 frames total; 12 seconds to clear	Time per shot, averaged over buffer length of 33 frames. Once buffer is full, slows to an average of 0.61 second or 1.63 fps, with a lot of variation.
Continuous Hi Large SuperFine JPEG	0.19 second (5.21 frames per second); 20 frames total; 15 seconds to clear	Time per shot, averaged over buffer length of 20 frames. Once buffer is full, slows to an average of 0.58 second or 1.73 fps, with a lot of variation.
Continuous Hi RAW	0.19 second (5.22 frames per second); 13 frames total; 13 seconds to clear	Time per shot, averaged over buffer length of 13 frames. Once buffer is full, slows to an average of 1.12 second or 0.89 fps, with a lot of variation.
Continuous Hi RAW + LSF JPEG	0.19 second (5.16 frames per second); 9 frames total; 13 seconds to clear	Time per shot, averaged over buffer length of 9 frames. Once buffer is full, slows to an average of 1.76 seconds or 0.57 fps, with a lot of variation.
Flash recycling	3.7 seconds	Flash at maximum output.
*Note: Buffer clearing times measured with a SanDisk Extreme III 8GB SDHC memory card. Slower cards will produce correspondingly slower clearing times. Slow cards may also limit length of bursts in continuous mode. ISO sensitivity and other settings such as D-Range or NR can also affect cycle times and burst mode performance.

Shot-to-shot cycle times are very good, at about 0.25 seconds for any quality setting. Continuous speeds are also very good, at about 5.2 fps for any quality in the Continuous Hi mode. Buffer depths are quite good too, at 20 Large Superfine JPEG frames, 13 RAW and 9 RAW + LSF JPEGs. (Note that our target image for this test is difficult to compress, so you'll likely get longer bursts with more typical subjects.) The flash takes 3.7 seconds to recharge after a full-power shot, which is good considering its power.

Download Speed
Windows Computer, USB 2.0	6,251 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, download speeds are quite fast as well.

Bottom line, the Pentax K-7 is a very responsive camera, and faster than the K20D in most respects.

Battery
Excellent battery life for a lithium-ion design.

Operating Mode	Number of Shots
Lithium-ion Rechargeable Battery, Optical Viewfinder (CIPA standard)	740
Lithium-ion Rechargeable Battery, Live View LCD	Not Specified

The Pentax K-7 uses a custom rechargeable lithium-ion battery for power, and ships with a charger. Battery life is excellent when using the optical viewfinder, but will most certainly be much less when using the LCD in Live View mode. Although battery life is well above average, we recommend you pick up a spare battery and keep it freshly charged and on-hand for extended outings, or if you plan to use Live View or shoot video. Pentax also offers the optional D-BG4 Battery Grip for the K-7, which accepts either a second lithium-ion battery pack, or six AA batteries.

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-7 accepts SD/SDHC memory cards, and no card is included with the camera.

Image Capacity with 1GB Memory Card		SuperFine (****)	Fine (***)	Normal (**)	Basic (*)	RAW
4,672 x 3,104	Images (Avg size)	75 13.6MB	120 8.5MB	213 4.8MB	420 2.4MB	41 24.6MB
	Images (Avg size)	75 13.6MB	120 8.5MB	213 4.8MB	420 2.4MB	41 24.6MB
	Approx. Compression	3:1	5:1	9:1	18:1	0.9:1
3,936 x 2,624	Images (Avg size)	105 9.7MB	168 6.1MB	296 3.5MB	576 1.8MB	-
	Images (Avg size)	105 9.7MB	168 6.1MB	296 3.5MB	576 1.8MB	-
	Approx. Compression	3:1	5:1	9:1	17:1	-
3,072 x 2,048	Images (Avg size)	171 6.0MB	275 3.7MB	478 2.1MB	915 1.1MB	-
	Images (Avg size)	171 6.0MB	275 3.7MB	478 2.1MB	915 1.1MB	-
	Approx. Compression	3:1	5:1	9:1	17:1	-
1,728 x 1,152	Images (Avg size)	527 1.9MB	819 1.3MB	1,414 724KB	2,594 395KB	-
	Images (Avg size)	527 1.9MB	819 1.3MB	1,414 724KB	2,594 395KB	-
	Approx. Compression	3:1	5:1	8:1	15:1	-

We strongly recommend buying either a large capacity SDHC card, at least a 2GB card, preferably a 4-8GB one, to give yourself extra space for extended outings. (Check the shopping link above, cards are really cheap these days, so no reason to skimp.)