Following DPReview publising its Sony a9 III studio test shots, PetaPixel wrote about our hands-on experience with the a9 III’s image quality. We wanted to add more context to that discussion, even if it spoils parts of our impending review.
Much of this underwhelming image quality performance is due to pure and simple physics. With all rows of the global shutter image sensor exposing an image simultaneously, which results in the a9 III’s impressive and complete elimination of rolling shutter artifacts, there also comes a need for additional electronics in the image sensor.
As Professor Bob Newman explained on Amateur Photographer in November, and PetaPixel described, the a9 III’s global shutter image sensor’s additional stuff restricts the maximum amount of light that the camera’s sensor can accept. This is, of course, related to the base ISO being 250 because the a9 III’s sensor, by its very design, is less sensitive to light than the sensor in the a9 II with its native base ISO of 100.
To see a stop or more of additional noise and to lose some maximum dynamic range then makes perfect sense. As impressive and groundbreaking as the a9 III’s sensor is, it cannot overcome physics — no camera can. If less light can make its way into the ever-vital photodiodes, image quality will be harmed, all else equal.
However, perhaps some of what was lost in the coverage yesterday, given that the entire story was only about image quality, is what photographers receive in exchange for this image quality hit. And after having shot with the a9 III for a couple of weeks, there is a lot the camera offers.
Beyond some critical ergonomics improvements and overall user experience I will describe in my full review, the a9 III’s 24-megapixel global shutter image sensor drives some of the camera’s most impressive performance specs and features.
For example, the a9 III’s continuous shooting speeds are remarkably impressive. The camera can shoot full-resolution images, including RAW files, at up to 120 frames per second with full AF/AE metering. This is a complete and total game-changer for sports, action, and wildlife photographers. Plus, if there’s enough light, photographers can do that with shutter speeds as high as 1/80,000s, although shutter speed is currently capped at 1/16,000s for the a9 III’s fastest continuous shooting speeds — we have been told this will be tweaked with future firmware updates.
Further, because of the nature of the global shutter, this action-stopping performance has no rolling shutter. Ever. Whereas a traditional CMOS image sensor reads out pixels row by row, which can mean that fast-moving objects are in different locations in the frame at various points during a single exposure, the a9 III’s global shutter kicks all that distracting and unsightly nonsense to the curb. Warped sports balls and weird-looking bats, clubs, and sticks are a thing of the past.
This has all been known since the a9 III was announced, though. Some of these features were adequately tested at Sony’s New York City launch event at the company’s carefully curated shooting experiences. However, what an event like that lacks — besides production-level firmware on the cameras, which limits specific testing — is actual real-world shooting experience.
So far, while the a9 III’s image quality has been only so-so in some respects during real-world testing and processing, the camera’s autofocus has been absurdly good. When someone, myself included, says, “Oh, I wouldn’t have been able to get this shot with camera X,” that can sometimes be a bit of an exaggeration. The shot is usually possible, albeit perhaps with more effort, time, or luck.
The a9 III, on the other hand, has delivered a hit rate, even at 60 and 120 frames per second, on fast-moving subjects that no camera I’ve used can match. My border collie, Eevee, is fast. That’s not a brag, because how the heck could it be, but she routinely runs nearly 30 miles per hour and changes direction on a dime.
I have photographed her a lot over the years, and it has nearly always been an exercise in frustration. Even the Sony a1, which I think still makes a strong case for the best camera overall, struggled in more straightforward shooting scenarios than the a9 III eats for breakfast.
To achieve all that — industry-leading shooting speeds, no more rolling shutter, and the best autofocus performance I’ve seen — is a significant accomplishment.
There is also the ability to sync flash at any shutter speed, which should not be ignored but is not something I have personally tested. Chris and Jordan are likely to address that with their hands-on experience. I suspect the a9 III’s lack of dynamic range and middling resolution power will limit the camera’s appeal for portrait and studio work. Still, there will undoubtedly be certain situations where the flash sync powers outweigh the image quality tradeoff.
Whether the a9 III’s relatively lower peak dynamic range is due to the base ISO being higher — it is — or its higher noise resulting from the new sensor design — also true — these two downsides are balanced by the a9 III’s most spectacular features, namely its shooting speed and elimination of rolling shutter.
The precise way these pros and cons balance out will depend heavily upon the photographer and what they intend to use the a9 III for. While other similarly priced cameras like the Sony a1 and Nikon Z9 deliver superior all-around performance and better image quality, they can’t match the a9 III’s speed, and they certainly cannot pull off the same special tricks concerning rolling shutter and flash sync. The a9 III can do some things no other can, even if the camera is not the versatile jack-of-all-trades that its $6,000 price tag suggests it might be.
Global shutter sensor technology is in its infancy for full-frame mirrorless camera systems. Sony is the first across the line, and that comes with costs — but ones that many professional photographers will be more than happy to pay.