Sony has announced its latest full-frame Alpha mirrorless camera, the Sony Alpha 9 III (a9 III). The headline feature of the new camera is that it has a global shutter.
What’s a global shutter?
There are two types of sensors for cameras that capture video: rolling shutter or global shutter. Most cameras use a rolling shutter sensor as they are cheaper to manufacture and offer a greater dynamic range. However, rolling shutter sensors capture the image for each frame one horizontal line at a time. Although this happens very quickly (usually under 25 milliseconds) it can cause distortion with moving items. However, a global shutter captures the whole image for each frame at the same time. This is the same way celluloid film works.
The Sony a9 III
The Sony a9 III uses the world’s first global shutter full-frame stacked CMOS image sensor. The sensor has approximately 24.6 effective megapixels and built-in memory. The new camera also features the latest BIONZ XR image processing engine. Sony says that the global shutter sensor enables the camera to shoot images at burst speeds of up to 120 frames per second with no rolling shutter distortion or camera blackout.
Video recording
The global shutter in the a9 III delivers distortion-free images for videos as well as still images. The new camera is the first in the Alpha series which can record 4K 120p high-frame-rate video without cropping. You can also shoot high-resolution 4K 60p videos with 6K oversampling. The a9 III features S-Cinetone, which can create a cinematic look straight out of the camera without post-processing. In addition, you can use S-Log3 and import your own LUTs (Lookup Tables).
Autofocus
The a9 III employs high-density focal plane phase-detection AF. And the designated AI processing unit also uses Real-time Recognition AF so the camera can recognize a wide variety of subjects. Importantly, the AI processing unit in the a9 III supports movies as well as still photography. Sony says the Real-time Recognition AF and Real-time Tracking provide a significant improvement in human eye recognition performance. This means the camera will automatically recognize, track and focus on the eyes of a specified subject.
Other features
The a9 III has a 4-axis multi-angle touchscreen LCD monitor. It also features an electronic viewfinder with a 9.44 million-dot Quad XGA OLED. Sony says this achieves high visibility with the same brightness as the Alpha 7R V and a magnification of approximately 0.90 times. The a9 III records to two media slots that support CFexpress Type A cards as well as SD cards. In addition, the camera can transfer data up to twice as fast as the Alpha 9 II and has five GHz Wi-Fi connectivity.
What we think
The global shutter in the Sony a9 III is big news. Camera manufacturers have worked to reduce the rolling shutter jello effect on newer cameras, but there are still issues with fast movement. However, global shutters deliver video that looks like movie film where motion is concerned. Unfortunately, the downside of global shutters in the past has been a reduced dynamic range which results in a less cinematic look. So we can’t wait for some video samples from the a9 III to see how the sensor looks. If the global shutter is a success hopefully Sony will use it in future versions of the company’s Cinema Line cameras such as the FX3 and FX6.
Pricing and availability
The Sony a9 III is available for pre-order now for delivery in Spring 2024. It retails at $5,999.
