Sony RX10 IV Performance

Very fast AF and incredible burst performance, but slow buffer clearing.

Startup to first shot time was slightly faster than average for its class. Play to Record switching was quite fast. Both times are about 0.2 second faster than the RX10 III.

The Sony RX10 IV's full single-shot autofocus shutter lag when shooting the same target multiple times was incredibly fast for a long-zoom camera, and much faster than the Mark III's. The RX10 IV's full AF shutter lag clocked in at only 34 milliseconds at wide angle using center AF mode. Full AF shutter lag was just a little slower at full telephoto, at about 36 milliseconds. In comparison, the RX10 III took about 196 and 218 milliseconds respectively. Enabling the flash raised full AF shutter lag to about 0.12 seconds as a result of the metering preflash, though that's still quite fast. The Mark III took about 0.28 seconds.

Manual focus shutter lag was about the same as with autofocus, at only 35 milliseconds, compared to 101 milliseconds for the Mark III. Prefocused shutter lag was extremely low at only 9 milliseconds, one of the lowest shutter lag times we've measured in recent memory. The Mark III took 24 milliseconds.

Shot-to-shot cycle times were excellent in single shot mode, at less than 0.3 second for Large/Extra Fine JPEGs or RAW+Large/Fine JPEG files. Note that the Sony RX10 IV does not support capturing JPEGs using highest quality Extra Fine compression when shooting with RAW files, dropping JPEGs down to Fine quality. We no longer test just RAW file cycle time in single-shot mode, as it's usually somewhere in between JPEG and RAW+JPEG.

The Sony RX10 IV's Continuous Hi shooting mode burst rate was incredible, able to capture best quality Large Extra Fine JPEGs and RAW+JPEG files at 23.8 frames per second and just RAW files a little faster at 24.2 frames per second, and the Mark IV supports continuous autofocus at those speeds! The RX10 III's top speed was 14.2 fps for JPEGs and 8.0 fps for RAW or RAW+JPEG, and AF is locked at the first frame. The RX10 IV also offers Mid and Lo settings rated at 10.0 and 3.5 fps respectively, however we didn't test those modes in the lab.

Buffer depths were outstanding at 217 best quality JPEGs, 112 RAW or 107 RAW+JPEG files before the camera slowed down, compared to 44, 29 and 25 frames respectively for the Mark III, despite the much faster burst.

As we've come to expect from Sony buffer clearing was quite slow, though, taking a whopping 230 seconds after a max-length burst of best quality JPEGs, 35 seconds for a max burst of RAW files, and 105 seconds for a max burst of RAW+JPEG files with our fast UHS-II SDXC card. You can make some setting changes and review images which have been written to the card while the buffer is clearing, but you can't access the main menu system at all until all images are flushed to the card. Unfortunately, like the RX10 Mark III, the Mark IV does not support the faster UHS-II interface. (Note that our Lexar Pro UHS-II card is also about as fast in UHS-I mode as the fastest UHS-I cards on the market so we didn't test the RX10 IV with our usual SanDisk Extreme Pro UHS-I card.)

The built-in flash took an average of 2.2 seconds to recharge after a full-power discharge, which is quite good and a little faster than the Mark III's 2.7 seconds.

Bottom line, the Sony RX10 IV's performance was outstanding in most respects with very fast AF, extremely low shutter lag, fast cycle times and an incredible ~24 fps full-res burst rate with deep buffers (and continuous autofocus is supported!). Buffer clearing was however quite slow and the camera locks you out of the menu during clearing, our only real complaints in terms of performance.

Battery Life
Good battery life for its class.

The Sony RX10 IV uses a custom NP-FW50 rechargeable lithium-ion battery for power, and the battery is charged in-camera via the USB port. CIPA battery life is similar to its predecessor, at 400 shots when using the LCD monitor, and 370 shots when using the electronic viewfinder. (The RX10 III was rated at 420 shots with the LCD and the same 370 shots with the EVF.) That's good battery life for a long-zoom, but we still recommend you pick up a spare battery for extended outings.

The table above shows the number of shots the camera is capable of (on 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))