6 hours ago
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Sony E-mount shooters have waited a long time for an affordable way to reach 400mm, and now there's a lens built specifically for that job. The catch sits right in the name: a maximum aperture of f/5.6 that darkens to f/8 as you zoom in.
Christopher Frost puts the Sony FE 100-400mm f/5.6-8 OSS through his usual independent testing, and he's upfront that "low budget" is relative. At $848,, this actually costs a touch more than Canon's RF-mount equivalent that arrived a few years earlier. Still, it gets you to 400mm without the weight or price of Sony's bigger telephoto options, and it comes with a lens hood in the box. It also plays nicely with Sony's 1.4x and 2x teleconverters, though your aperture drops into genuinely dim territory once you attach them.
That dark aperture is the whole story here, and it cuts both ways. Frost points out that f/5.6 to f/8 rules out the creamy backgrounds you'd get from faster glass, and sports work becomes tricky unless you're in bright sun or comfortable pushing ISO. The upside is size and weight. At 654 g, roughly 1.5 lbs, this lens carries almost like a traditional 70-300mm, and Frost describes its stretched-out shape as almost comical. The build is plastic with a metal mount and light weather-sealing, and the autofocus impressed him in continuous mode, staying quick even with the 2x converter attached and the aperture sitting at f/16.
If you shoot birds or wildlife, 400mm is a sensible floor rather than a luxury, and this lens sits squarely in a wider shift toward lightweight, slower telephoto zooms that trade one stop of light for portability. The principle worth taking away applies well beyond this one lens: a variable aperture that ends at f/8 pairs best with modern bodies that handle high ISO cleanly, so the camera in your bag matters as much as the glass on the front. Frost's testing on the 61-megapixel Sony a7CR is essentially a worst-case scenario, since that sensor demands more from any lens than a 24- or 33-megapixel body would. Match this zoom to a lower-resolution sensor and its softness becomes far less noticeable, which is exactly the pairing many casual wildlife shooters already own.
The image quality results follow a familiar pattern. Sharpness in the center is very good at 100mm and reaches excellent once you stop down to f/8, while the corners stay softer with some blue color fringing that never fully clears. Zoom to 400mm and the center holds up reasonably well, with contrast improving noticeably at f/11, though it never turns razor sharp. Distortion stays low across the range, close focusing reaches an impressive 86 cm at the long end, and flare resistance is strong even zoomed all the way in. Frost's advice on the teleconverters is worth hearing before you spend on one, and there's more detail in the video on how the 1.4x holds up compared to the 2x.
Give the video above a watch to see Frost's sample footage and hear his full verdict on whether that dark aperture is a dealbreaker.
English (US) ·