Sony A7R III Performance

Generally excellent performance, however startup and mode switching is sluggish, and buffer clearing can be quite slow.

Powerup to first shot was sluggish compared to DSLRs, and slightly slower than the 1.5 seconds we measured for the A7R II. Switching from Play to Record mode and taking a shot was also slower than the A7R II's 0.9 second.

Looking at the Sony A7R III's ability to determine that it's properly focused when shooting the same, static target multiple times without defocusing between shots (our standard test), its autofocus speeds were decent for a mirrorless ILC, though oddly a bit slower than the A7R II. The Sony A7R III's full-autofocus shutter lag (with the subject at a fixed distance) was 0.251 second in Single-area (center) AF-S mode versus 0.212 second for the Mark II with the same lens. Sony's "up to two times faster AF speed" claim for the Mark III versus the Mark II is however qualified by "in low light conditions," while this test is performed in bright light to achieve shutter speeds fast enough to freeze the timer values. In the field the Mark III's autofocus speed with real-world subjects was definitely faster and more capable than its predecessor's.

When manually focused, the Sony A7R III's lag time dropped to 0.105 second, just a bit faster than the 0.107 second we measured for the A7R II.

The Sony A7R III's prefocused shutter lag was a fast 0.023 second, just slightly slower than the A7R II's 0.020 second.

The above tests were all done with the mechanical shutter and with first-curtain electronic shutter enabled (the default mode). Switching to Silent Shooting mode which uses an all-electronic shutter increased lag times significantly as you can see in the bottom half of the table above, so that's something to keep in mind.

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.

Single-shot cycle times were very fast, at less than 0.3 second for both Large/Extra Fine JPEGs and RAW + Large/ Extra Fine JPEG frames. (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 modes. Also note that the A7R III can capture highest quality "Extra Fine" JPEGs together with RAW files, which we believe is a first for Sony. Previous models limited JPEG quality to "Fine" when shooting RAW+JPEG.)

The Sony A7R III's fastest Continuous Hi+ burst mode is rated at max 10 frames per second regardless of shutter type used, so we just tested with the default mechanical shutter. When shooting Large/Extra Fine JPEGs, the A7R III essentially met Sony's spec at 9.9 frame per second, however it slowed down a bit to 9.1-9.2 fps when shooting uncompressed RAW and uncompressed RAW+ Large/Extra Fine JPEG frames. Still, that's impressive for the resolution and a massive improvement over the A7R II which topped out at 5 fps. The A7R III also offers 8 (Hi), 6 (Mid) and 3 (Lo) frames-per-second modes with both the mechanical and electronic shutter.

Buffer depths in Continuous Hi+ mode slightly exceeded Sony's spec of 76 Large/Extra Fine JPEG, 28 uncompressed RAW, and 28 for uncompressed RAW + Large/Extra Fine JPEG frames, testing at 82, 30 and 30 frames respectively in the lab. That's over twice as many frames as the A7R II could manage despite the almost double burst speeds. We didn't test Compressed RAW files, however Sony claims Compressed RAW and all three JPEG qualities (Extra Fine, Fine and Standard) have a 76 frame buffer.

Buffer clearing times were quite slow even with our very fast Lexar Pro 2000x UHS-II card in the UHS-II compatible slot, though, ranging from a whopping 57 seconds after 82 Large/Extra Fine JPEGs to a more tolerable 14 seconds after 30 uncompressed RAW files. However unlike the A7R II, the Mark III lets you access the menu and change settings while the buffer is clearing, a welcome improvement.

Bottom line, the Sony A7R III's overall performance is excellent for its class, and much improved over the A7R II in terms of cycle times, burst speed and buffer depths. However startup time, mode switching and AF speeds actually tested a bit slower than the A7R II in the lab, and buffer clearing can still be quite slow despite the addition of UHS-II card support.

Very good battery life for a mirrorless camera.

The Sony A7R III uses a custom NP-FZ100 rechargeable lithium-ion battery pack for power, and comes with battery and a dedicated charger even though in-camera charging is also supported. The battery is CIPA-rated for 530 shots per charge when using the electronic viewfinder and 650 shots when using the LCD monitor. That's well above average for a mirrorless camera and almost double what the A7R II offered with its smaller battery, but it's still well below most prosumer and pro DSLRs when using their optical viewfinders. An optional VG-C3EM vertical grip is however available which doubles battery life with two batteries.

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))