Sigma (Sort of) Makes More Lenses Work with the a9 III’s 120fps Mode

Jul 26, 2024

Jeremy Gray

A close-up of a person holding a Sony camera with a large lens attached. The individual is wearing a beige, textured top and blue jeans, with the camera hanging by their side. The background is softly lit with blurred, neutral tones.

Sigma has released lens firmware updates for three E-mount lenses, making them compatible with the Sony a9 III camera in its class-leading 120 frames-per-second shooting mode. This brings the total number of Sigma lenses compatible with the a9 III to 10.

The Sigma 14-24mm f/2.8 DG DN Art, 50mm f/1.4 DG DN Art, and 105mm f/2.8 DG DN Macro are now all compatible with the a9 III’s 120 FPS drive mode, joining Sigma’s 28-70mm f/2.8, 60-600mm f/4.5-6.3, 100-400mm f/5-6.3, 150-600mm f/5-6.3, 35mm f/1.4, 85mm f/1.4, and 500mm f/5.6 lenses.

However, there is a significant caveat. The updates may allow these 10 Sigma lenses to work with the Sony a9 III when it shoots at 120 frames per second, but the lenses cannot continuously autofocus at this speed. Instead, the lenses are only compatible with 120 frames per second shooting when used in AF-S autofocus drive mode or with manual focus.

PetaPixel contacted Sigma, requesting clarifications concerning its lenses and the Sony a9 III, including questions concerning why lenses cannot be used with AF-C at the a9 III’s fastest shooting speeds. Sigma has yet to respond, but the article will be updated if the company offers additional information.

Not even all Sony lenses are fully compatible with the a9 III’s 120 FPS drive mode. It is an exceptionally fast shooting speed, and it is challenging for lenses to keep up. Sony’s compatibility list includes many — but not all — of the company’s lenses, and some lenses have restrictions concerning their apertures during 60 and 120 FPS shooting.

While Sigma now has 10 lenses that can technically be used to shoot at 120 FPS on the Sony a9 III, all Sigma lenses are still limited to a maximum speed of 15 FPS when used with continuous autofocus. Admittedly, this is still reasonably quick and will be sufficient in many situations. However, photographers who want to take advantage of the a9 III’s highlight feature — high-speed shooting — will still want to stick with Sony’s fully compatible lenses.

Hopefully, this limitation can be addressed at some point, although it’s not clear precisely who is responsible for it in the first place. The consensus lies blame at Sony’s feet, but in the case of the a9 III, there are indeed engineering challenges to achieve continuous focus at full speed, too.

Image credits: Sigma