Sony’s a9 III Light Speed imaging technology

The groundbreaking a9 III from Sony is the first of its kind in the full-frame interchangeable lens mirrorless (ILC) camera realm, boasting a global shutter that enables impressive performance, such as capturing 120 frames per second. However, it does not support the most recent CFexpress specification.

This innovative sports and action-centric mirrorless camera comes equipped with a 24.6-megapixel CMOS global shutter sensor, allowing it to record up to 120 frames per second while maintaining full autofocus and auto exposure tracking and metering capabilities. Additionally, it can capture images in 14-bit RAW format—though compressed—resulting in a substantial data rate of 6GB/s.

Memory card performance in the Sony a9 III

Needless to say, such large volumes of data necessitate speedy memory cards, seeing as the a9 III possesses a buffer depth of only 1.6 seconds when firing at maximum frame rates. This means that an ultra-fast memory card is required in order to sustain shooting at the highest possible burst for extended periods.

Understanding the a9 III’s complex performance characteristics

Despite this assumption, the a9 III is a complex camera with numerous aspects that influence its performance. For instance, while the camera can reach a maximum burst time of 1.6 seconds at 120 frames per second—which equates to capturing 192 images—Sony claims that the actual upper buffer limit is close to 700 shots. Thus, at reduced frame rates, the camera is capable of shooting continuously for significantly longer durations.

Buffer capacity vs. burst speed: Resolving the a9 III’s constraints

The camera is unable to sustain 120 frames throughout its entire buffer capacity. Although the company didn’t provide any clarification regarding this issue, PetaPixel speculates that it could be due to heat, processing power, or a combination of both.

Pre capture mode

Additionally, the a9 III includes a Pre Capture mode that starts buffering before the shutter is entirely pressed. When using this mode, the buffer gets automatically maximized. If a photographer captures at 120 frames per second, where the buffer limit is 1.6 seconds, the Pre Capture mode significantly alters the duration a photographer can shoot after pressing the shutter.

Dynamic Adjustments in Burst Shooting and a9 III’s Frame Rate Management

At first glance, it seems as though the camera’s limitation lies in its ability to clear its own buffer; however, that may not be the case. Sony also notes, albeit without elaboration, that the camera dynamically regulates its frame-per-second capture speed during burst shots. If maintaining 120 frames proves challenging, for instance, it will reduce to a sustainable rate before picking up pace again. Sony doesn’t go into detail about this dynamic adjustment since it varies depending on the shooting situation and resultant variables are too numerous for providing a single explanation.

The missed opportunity with CFexpress 4.0 and Sony’s strategic choices

Regardless, it’s rather perplexing that Sony didn’t incorporate support for the latest CFexpress standard. CFexpress 4.0 offers double the speed of its predecessor and would have afforded a9 III photographers twice as much processing power when dealing with large quantities of images – an opportunity that unfortunately didn’t materialize.

Consequences of Sony’s decision against CFexpress 4.0

Sony was well aware of the upcoming CFexpress 4.0 standard long before its announcement but still decided against incorporating it into the a9 III. It’s also important to highlight that CFexpress 4.0 is entirely backward compatible without any drawbacks, signifying that there would be no downsides for users if it were included.

CFexpress Type A vs. Type B: A Matter of Size and Speed

Sony has opted to persist with the CFexpress Type A format, which possesses the advantage of being compact enough to share a card slot with an SD card. However, it only has half the PCIe bus lanes compared to CFexpress Type B, the card format utilized by Nikon and Canon. Consequently, even within the prior CFexpress 2.0 standard, Sony’s data transfer rate to a card is only half as fast as its rivals.

Despite this issue, Sony has claimed that all photographic features in the a9 III can function on UHS-II SD cards. As such, photographers won’t feel compelled to use the costlier CFexpress Type A cards unless they desire particular video features like S&Q and 4K at 120p in some file formats. In addition, clearing the camera’s buffer will naturally take longer on an SD card when compared to a CFexpress card.

When the new CFexpress standard was revealed, photographers were informed that they would require updated camera hardware to leverage the enhanced speeds that CFexpress 4.0 offers. Unfortunately for Sony users, they must continue waiting despite having what many consider the most outstanding professional camera in recent memory.

The Sony a9 III, anticipated to be the leading camera choice for sports photographers from Sony for several years, will unfortunately not be able to utilize the latest generation of CFexpress memory cards. Even though these memory cards are not available yet – a fact that Sony quickly pointed out, despite being a memory card manufacturer with the power to change this situation – they have the potential to exist, as demonstrated by the Type B cards already making their way into the market.

Sony a9 III’s practical speed limitations

While some may perceive this as a minor issue, it’s indeed slightly irksome when considering the context. The Sony a9 III is undeniably the most impressive camera produced by Sony in recent years and is expected to play a significant role in its lineup for quite some time. It’s simply disheartening that this extraordinary camera will face limitations in terms of practical speed capabilities right from the start due to its hardware constraints.