Panasonic GX8 Performance

Timing and Performance

Generally very good performance for a mirrorless ILC.

Startup/Play to Record

Power on
to first shot

~1.2 seconds

Time it takes to turn on and capture a shot.

Play to Record,
first shot

~0.6 second

Time until first shot is captured.

Startup time was a little faster-than-average for a mirrorless camera, and switching from Play to Record and taking a shot was fairly quick.

Shutter Response (Lag Time)

Full Autofocus,
Single-area AF mode

0.177 second

Time from fully pressing shutter button to image capture, with the lens already at the proper focal distance setting.

Full Autofocus
Single-area AF mode
Flash enabled


Time from fully pressing shutter button to image capture. Auto Flash enabled. (No built-in or bundled flash.)

Manual Focus

0.065 second

For most cameras, shutter lag is less in manual focus than autofocus, but usually not as fast as when the camera is "prefocused".


0.058 second

Time to capture, after half-pressing and holding shutter button.

The Panasonic GX8's autofocus speed was very good our tests, especially for a camera that uses contrast detection only. The GX8 produced full-autofocus shutter lag (with the subject at a fixed distance) of 0.177 second using 1-area (center) AF. That's quite good for a mirrorless camera and competitive with most prosumer DSLRs. When manually focused, the GX8's lag time dropped to 0.065 second, also very good. The GX8's prefocused shutter lag time was 0.058 second, also quite fast.

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.

Cycle Time (shot to shot)

Single Shot mode
Large/Fine JPEG

< 0.3 second

Time per shot, averaged over a few frames (we no longer test for buffer depths in single-shot mode).

Single Shot mode

< 0.3 second

Time per shot, averaged over a few frames (we no longer test for buffer depths in single-shot mode).

Early shutter


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 H
Large Fine JPEG

0.12 second (8.26 frames per second);
>300 frames total;
20 seconds to clear*

Time per shot, with no apparent limit.

Continuous H

0.13 second (7.94 frames per second);
36 frames total;
22 seconds to clear*

Time per shot, averaged over buffer length of 36 frames, then slows to an average of 0.60s or 1.66 fps.

Continuous H

0.13 second (7.94 frames per second);
32 frames total;
39 seconds to clear*

Time per shot, averaged over buffer length of 32 frames, then slows to an average of about 1.04s or 0.96 fps.

Flash Recycling


No built-in or bundled flash.

*Note: Buffer clearing times measured with a SanDisk Extreme Pro 95MB/sec UHS-I 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.

Single-shot cycle times were so fast that they were difficult to accurately measure as they depend on the tester's dexterity and ability to maintain an optimum rhythm, so your results may vary. (Note that we no longer test single-shot mode with just RAW files, as the results are usually somewhere in between JPEG and RAW+JPEG.)

Continuous High Speed "H" mode burst rate was quite good for its class at 8.3 frames per second for best quality JPEGs, slightly exceeding Panasonic's 8 fps spec. When shooting RAW or RAW+JPEG files, the frame rate dropped only slightly to 7.9 fps, which is still quite good. Note that these burst rates are with single-shot AF mode (AFS). Panasonic claims up to 6 fps with continuous autofocus (AFC). The GX8 also offers Middle Speed (rated at about 6 fps) and Low Speed (rated at 2 fps) modes, however we did not test those modes.

The GX8 has an all-electronic shutter mode which the company says boosts the full-resolution frame rate to 10 fps with AFS, but when we tested it in the lab, it was actually slower than with the mechanical shutter (~7.2 fps for RAW+JPEG mode), so we didn't test with it further. A Super High Speed mode which uses the all-electronic shutter is also available which captures Small JPEGs (5 megapixels at 4:3) at 40 frames per second for up to 120 frames, however we did not test that mode in the lab.

Full-resolution buffer depth was essentially limited only by card capacity when shooting Large/Fine JPEGs. When shooting RAW files buffer depth was 36 frames, and 32 frames when shooting RAW+JPEG files, which is quite generous.

Buffer clearing was pretty slow with a fast 95MB/s UHS-I card, ranging from 20 seconds after a long burst of JPEGs to 39 seconds after a 32-frame burst of RAW+JPEG files. You can however take additional photos and adjust settings while the buffer is clearing. Oddly, there's no mention of UHS-II support for the GX8, but we tried a UHS-II card anyway. Unfortunately it didn't improve buffer depths or clearing times, confirming the UHS-II interface is not supported.

Bottom line, the Panasonic GX8's performance is very good for its class. Startup and mode switching are reasonably fast, while autofocus speed and shutter lag are very good. Burst performance is very good, buffer depths are excellent, however buffer clearing is slow.

Battery Life

Below average battery life.

Operating Mode Battery Life
Still Capture, CIPA standard
(Monitor with
H-FS14140 or H-HS12035 lens)
330 shots
Still Capture, CIPA standard
(EVF with
H-FS14140 or H-HS12035 lens)
310 shots

The Panasonic GX8 uses a custom rechargeable lithium-ion battery pack for power, and comes with both a single battery and dedicated battery charger. The CIPA-rated 330 shots per charge when using the monitor and 310 shots with the EVF are below average for a mirrorless ILC (especially for one with no built-in flash), and much lower than a typical DSLR when using an optical viewfinder. We strongly recommend getting a second battery for your GX8 if you plan any extended outings.

The table above shows the number of shots the camera is capable of (on a fully-charged rechargeable battery), 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))


Editor's Picks