The Alpha a7R IIIA Mirrorless Digital Camera from Sony is a versatile, high-performance camera characterized by not only its resolution but by its multimedia versatility. This updated Fast Hybrid AF System employs a combination of 399 phase-detection points and 425 contrast-detection areas for quicker acquirement of focus in a variety of lighting conditions, and also maintains focus on subjects more effectively. 

Additionally, benefitting both stills and video operation, the a7R IIIA retains the 5-axis SteadyShot INSIDE sensor-shift image stabilization, which is now effective to minimize the appearance of camera shake by up to 5.5 stops. An updated rear 3.0" 2.36m-dot tilting touchscreen LCD is also available for intuitive settings control and to better support working from high and low angles. Suiting the camera's use in trying conditions, the magnesium alloy chassis and extensive weather-sealing also render the a7R IIIA dust- and moisture resistance. This sensor structure works with a gapless on-chip lens design and an anti-reflection coating, as well as eliminating the optical low-pass filter, to improve light collection and enhance detail.  

The BIONZ X processor also works in conjunction with a high-speed front-end LSI to realize faster processing times along with the ability to capture an impressive 15-stop dynamic range at low sensitivity values. If shooting in live view mode, a continuous shooting rate of up to 8 fps is also possible. This Fast Hybrid AF System now achieves twice the focusing speed and more reliable tracking compared to previous a7R models, as well as improved low-light focusing response down to -3 EV. Additionally, Eye AF can be used to base focus on recognized subjects' eyes for portraits and is available in both AF-S and AF-C modes.

Autofocus can also be used in conjunction with the Focus Magnifier function for critical focus when homing in on minute subject details. AF tracking sensitivity can also be customized in five steps to match how a subject is moving and frequently used focus point settings can be memorized and recalled with a custom button for faster switching between focus settings. This allows users to confidently use any lens, even adapted lenses, for critical imaging without encountering blur from camera shake. All 5 axes of stabilization will function at all times, even when used with third-party lenses and adapters or lenses with built-in optical stabilization.

Full HD 1080p recording is also supported in frame rates up to 120 fps, and both resolutions utilize the 100 Mbps XAVC S format contained within an MP4 wrapper with 4:2:0 sampling. These settings will allow you to slow down action as well as speed up a slow-moving scene. This setting is also NTSC/PAL switchable. A time code can be used to record hours, minutes, seconds, frames on image data for more precise editing while the User Bit function can record date, time, and scene number to aid in editing together footage from multiple cameras. Both Standard and High-quality settings can be used, depending on the shooting situation, in order to optimize the viewing experience.

This updated viewfinder design also affords the use of autofocus in the Focus Magnifier mode as well as improved focusing peaking to benefit manual focus operation. Magnesium alloy chassis assures rigidity, durability, and stability while remaining lightweight. The lens mount has also been improved to better support heavy lenses and the grip rigidity has been improved for more comfortable handholding. Using the same NP-FZ100 battery as the a9, the a7R IIIA has improved battery life and is now rated for approximately 530 shots per charge with the EVF or 640 shots with the rear LCD.

A USB 3.2 Gen 1 Type-C port has been added, in addition to a micro-USB port, for faster, more reliable tethering support. The USB Type-C connection allows the camera to be charged from the host power source while connected. These files can then be merged together during post-production by using the Sony Imaging software suite. An advanced 1200-zone evaluative exposure metering sensor delivers consistent and accurate results using multi-segment, center-weighted, or spot metering modes. Anti-flicker shooting automatically recognizes and times the shutter action to minimize the flicker effect for more consistent results on still images.