Sony's mirrorless system has matured in many ways since its 2013 launch. There are a bevy of first- and third-party lenses available, including ultra-wide-angle, macro, fast primes, and even specialty manual focus options. Telephoto coverage has been a weak point, though, with the FE 24-240mm F3.5-6.3 OSS as the longest telephoto option available to this point. The FE 70-300mm F4.5-5.6 G OSS ($1,199.99) extends that reach, although it doesn't have as much wide-angle coverage. It's an excellent performer, and a solid choice for covering wildlife and sports with the Sony system, especially when paired with an APS-C body like the Alpha 6300.

Design

The 70-300mm ($1,273.00 at Amazon) is a hefty lens, but reasonably sized for a telezoom with full-frame coverage. It measures 5.7 by 3.3 inches (HD) when set to the 70mm position, weighs about 1.9 pounds, and supports 72mm front filters. It extends when zoomed, and includes a lock switch so you can prevent the barrel from creeping out inadvertently when the lens is hanging downward. A reversible lens hood is included.

Like the full-frame Alpha 7 series and premium APS-C Alpha 6300 and 6500 models, the 70-300mm is sealed against dust and moisture. It's also optically stabilized, steadying shots when paired with bodies that don't feature sensor-based stabilization, and working in tangent with internally stabilized cameras to provide additional steadying.

There are a few toggle switches, as well as a control button, on the barrel. The button activates Focus Hold, so you can keep focus locked and recompose a shot before firing the shutter, even when the using AF-C. Switches control the focus mode (AF/MF), turn image stabilization on or off, and set the focus limit. You can let the lens hunt over its entire range, or only attempt to lock onto distant objects (3 meters to infinity), which will speed target acquisition when shooting subjects at a distance, and prevent objects that enter the frame at a closer distance from throwing off tracking.

Close focus is possible to 2.95 feet (0.9-meter), even at the 300mm position. That gives the lens a maximum 1:3 macro magnification when zoomed all the way in, projecting subjects onto the image sensor at one-third size. That adds a bit of versatility to the lens, and even though its maximum aperture is a modest f/5.6 when zoomed all the way in, the lens produces images with a shallow depth of focus when working near its minimum focus distance.

The zoom ring sits behind the front element and occupies a good swath of the barrel. It's finished in textured rubber and has markings at 70, 100, 135, 200, and 300mm. The manual focus ring sits behind it. It's narrower, but also finished in a rubber texture for better gripping. Like almost all lenses for the Sony mirrorless system, manual focus is electronic. It's not ideal for photographers who prefer the tactile feedback of a mechanical manual focus system, but this is a lens that's destined more for the autofocus crowd.

Image Quality

I tested the 70-300mm with the 42MP Alpha 7R II ($1,798.00 at Amazon) . At 70mm f/4.5 it scores 3,848 lines per picture height on Imatest's standard center-weighted methodology, an exceptional result. Performance is very even across the frame, with the mid parts and edges bettering 3,700 lines. When looking at photos from a high-resolution body like the 7R II we want to see 2,200 lines at a bare minimum. With this type of resolving power, you'll get crisp details even when making huge prints or cropping aggressively.

There's an uptick in fidelity as you stop down. At f/4.5 the score improves to 4,159 lines. It hits 4,176 lines at f/8 and peaks at f/11 (4,227 lines). Diffraction cuts into image quality at f/16 (3,915 lines), and is more of an issue at f/22 (2,804 lines).

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At 135mm the maximum aperture has narrowed to f/5. Image quality is superb, at 4,048 lines. It holds steady at f/5.6, and improves at f/8 (4,232 lines) and f/11 (4,240 lines). There's a slight drop at f/16 (3,937 lines) and a more significant one at f/22 (2,961 lines).

The maximum f-stop is f/5.6 at 200mm, where the lens loses a bit of sharpness. But it still scores 3,393 lines, with solid perofrmance through most of the frame. Edges are drifting toward the soft side, at 2,478 lines, which can be an issue if you're making huge enlargements, but isn't anything to worry about in most situations. You can stop down to f/8 if edge quality is more important—the average score jumps to 3,779 lines and edges show 3,141 lines. Image quality remains strong at f/11 (3,920 lines) and f/16 (3,866 lines), before diffraction rears its ugly head at f/22 (2,857 lines).

At 300mm f/5.6 the lens does just about as well as it does wide open at 70mm, an average of 3,822 lines, with strong performance from edge to edge. There's a slight uptick at f/8 (3,951 lines), and similar performance at f/11. The expected downward resolution trend shows itself at f/16 (3,625 lines) and f/22 (2,642 lines).

There is some visible distortion. At 70mm you get 1.6 percent pincushion distortion, which draws straight lines with a noticeable inward bow. It increases a bit at 135mm (1.9 percent), before dropping at 200mm (1.4 percent) and 300mm (0.8 percent). If you process images in software like Adobe Lightroom ($9.99/Month at Adobe) you can remove distortion with a single click.

Corner illumination is pretty solid throughout the zoom range. Wide open the lens hovers around -1EV at the corners (compared with the center). Stopping down one full stop cuts the deficit to about -0.5EV, which is negligible in real-world use.

Conclusions

The Sony FE 70-300mm F4.5-5.6 G OSS is a crisp, all-weather telezoom. It offers a solid range, balances well with both APS-C and full-frame Sony mirrorless cameras, and delivers crisp results throughout its zoom range. $1,200 is on the pricey side, but it's a price that's backed with very strong performance. Some photographers, especially those with an eye for wildlife, may find it too short, even when paired with an APS-C camera, and they'll have to continue to wait for a native Sony mirrorless lens with an extreme telephoto reach. But if a 70-300mm meets your needs, consider Sony's latest to be a strong option in the category.

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