Sony’s 100-400mm GM zoom adds constant f/4.5 and faster autofocus

Sony’s new FE 100-400mm F4.5 GM OSS is not trying to be the biggest telephoto in the bag. It is trying to be the one hobbyists can actually carry, handhold, and use when the action turns chaotic. Announced on May 13, 2026, and due in North America in June, the lens lands squarely in the wildlife, birding, sports, and photojournalism lane, with Sony putting the U.S. preorder price at $4,299.99.

The biggest change is the constant f/4.5 aperture across the full 100-400mm range. That matters most at the long end, where Sony’s previous 100-400mm GM design dropped to f/5.6. In practice, that extra brightness gives photographers more room to hold shutter speed, keep ISO in check, and separate a subject from the background when the light is less than perfect. For field work, that is not a minor tweak. It is the difference between fighting the lens and trusting it.

Sony also pushed hard on autofocus, saying the new zoom is up to approximately 3x faster than the older FE 100-400mm F4.5-5.6 GM OSS, with about 50% better subject tracking in its tests. The lens uses four custom-optimized XD linear motors, an internal zoom structure, and a stable center of gravity, all aimed at keeping it usable for long handheld sessions. Sony says it is fully compatible with the Alpha 9 III’s continuous shooting at up to 120 fps with AF/AE tracking, which tells you exactly which kind of photographer this lens is meant to impress.

The optics are built like a flagship tool, not a casual reach zoom. Sony says the formula uses 28 elements in 20 groups, including one ED XA element, one XA element, two Super ED elements, and three ED elements, plus Nano AR Coating II and an 11-blade circular aperture. DPReview reported a 328 mm length, a 95 mm filter thread, dust and moisture sealing, and a fluorine-coated front element. Photography Life added a maximum magnification of 0.25x, minimum focus distances of 0.64 m at 100mm and 1.5 m at 400mm, and teleconverter support out to 800mm, or 1,200mm in APS-C mode.

That is why this lens feels more like a working photographer’s update than a simple spec bump. At 1,840 g, it is still serious glass, but Sony is clearly aiming for the sweet spot between pro reach and day-long portability. Yang Cheng said the lens is meant to deliver “super-telephoto reach with G Master optical quality” in a body light enough to shoot handheld all day. The real answer is that it does both: it meaningfully expands what Sony shooters can capture in the field, while giving owners of the older 100-400 GM a very expensive reason to rethink what “good enough” looks like.