The Tamron 50-400mm F4.5-6.3 Di III VXD is one of our favorite full-frame superzoom lenses. Its combination of superb optical performance, accomplished autofocus and effective optical stabilization gives consistently sharp results throughout the lens' entire zoom range. This is a lens ideally suited to action, sports and wildlife photography: it enables you to zoom between a standard field of view and serious telephoto reach for different compositions, eliminating any risk of missing a fleeting shot due to swapping lenses.
Tamron 50-400mm F4.5-6.3 Di III VXD full review
The Tamron 50-400mm comes in Sony E and Nikon Z mounts, and Tamron has now released a firmware update for the E-mount edition. It states that with the new Ver.4 firmware, there's improved AF performance during zooming when shooting stills and video in AF-C mode. What's more, if you're using the lens on a Sony A9 III, its headline-grabbing 120fps continuous shooting will now work in conjunction with Tamron 50-400mm when the focus mode is set to AF-S, DMF, or MF.
However, this implies that 120fps shooting still isn't supported in AF-C mode; the very focussing mode you're most likely to want when shooting a continuous burst of stills. Granted, you'll still be able to track subjects moving across the image frame at a consistent distance from the camera, but you won't be able to maintain focus of a subject like a cyclist or racing car that's approaching you. We suspect Sony is still reserving 120fps burst shooting with AF-C for its own lenses, hence why Sigma and Tamron E-mount optics don't support it.
To update the firmware for your Tamron 50-400mm, simply download Tamron's Lens Utility software.