Sigma’s 100-400mm F5-6.3 for full-frame Sony mirrorless (and L-mount cameras) offers quite a bit of reach for under $1000. It’s a bit slower than some of Sony’s own E-mount telephoto zooms, but it’s a comparably light and affordable alternative for FE shooters looking to add a telezoom to their kits. Take a look at our gallery and see what it’s capable of.