Hands-on With Sony’s 100-400mm F/4.5-5.6 GM OSS Lens

December 1, 2017

By Theano Nikitas

Relatively compact, this 100-400mm GM feels well-balanced on the Sony a9.

Released alongside the Sony a9 last April, the FE 100-400mm F/4.5-5.6 GM OSS brings a telephoto zoom to the high-end Gold Master (GM) line and E-mount cameras. This is a welcome addition to the entire E-mount lineup, and with its exceptional design (and GM designation), this lens is best suited for photographers shooting with Sony high-resolution cameras such as the a7-series and the a9. I tested this $2,500 lens with the Sony a9.

The relatively lightweight and compact lens comes with a lens hood and tripod collar, and it offers advanced features such as focus hold buttons, a focus limiter switch as well as image stabilization and other equally useful features. It’s also compatible with Sony’s SEL14TC (1.4x) and SEL20TC (2.0x) teleconverters if you need more reach. Or, you can set your full-frame camera to a crop mode, as I occasionally did with the a9.

Although great for weddings, this lens is also perfect for capturing wildlife. Test Photos © Theano Nikitas

Image Quality

There’s no doubt that Sony engineers put a lot of thought and effort into this lens. Images captured throughout the zoom range were sharp from corner to corner and left little to the imagination when it came to fine details. Vignetting and chromatic aberration were, for the most part, so minimal that they were difficult to identify when they existed.

In combination with the a9, the 100-400mm lens was quick to focus on all but the fastest moving subjects. Since I’m not a seasoned bird or wildlife photographer, I imagine that those with more experience in the field will have a better hit rate than I did with birds flying overhead or taking off and landing in a pond. Still, I was impressed with the lens’s AF responsiveness and accuracy, with a hat tip to the a9’s tracking abilities.

Paired with the Sony a9, this lens easily captured this ice skater in action.


The lens is sturdily built yet it’s easily handheld, which is a big plus in my book. Without the tripod mount, it weighs 49.3 ounces and measure 3 ¾ x 8 1/8 inches (although the lens barrel extends when zoomed), which proved just light and small enough for me to forego a tripod.

A quartet of switches on the lens barrel allow you to shift between AF and MF, activate the focus range limiter (either full or from 3m to infinity) and turn image stabilization on and off. The fourth switch offers standard and panning IS options.

The lens, which is dust- and moisture- proof, also comes equipped with three focus hold buttons that can be programmed for a number of different functions, including
eye-AF, AF ON, focus hold and more.

In addition to a polarizing filter window on the lens hood, the FE 100-400mm GM lens also features a zoom lock. This slim ring tightens or loosens the zoom tension and is most useful for preventing lens creep. Set somewhere in the middle, I was able to smoothly zoom the lens without much lens creep when the lens was tilted down.

What We Liked

Of course, the sharp, well-detailed images are at the top of the list but the lens is equipped with options designed to implement critical functions quickly and easily with its four on-barrel switches. The lens works exceptionally well with the a9, providing excellent image stabilization and fast, accurate AF. Being able to customize the focus hold buttons is a huge plus, too.

What We Didn't Like

It’s not that there was anything we really didn’t like about the lens. Rather, I put together a wish list for an even lighter, smaller lens with a faster aperture (yes, I know I’m dreaming). That would make it better balanced with more compact mirrorless cameras. Ideally, I’d love to be able to program each of the three focus hold buttons with different functions. And, because I have relatively small hands, the buttons need to be closer to the camera body to be within easy reach—but that’s just me.

How It Compares

At this point, there’s really no direct competition for this FE 100-400mm lens. While Sigma offers an f/5-6.3 version and Tamron recently announced a lighter 100-400mm f/4.5-6.3 model, neither one (so far) is available with a Sony E-mount—only Canon and Nikon. I’m very curious about the new Tamron, though, especially since it weighs only 39.3 ounces. We’ll fill you in when we get some hands-on time with the Tamron lens.

Bottom Line

With its compact size, speed, excellent image quality and versatility, this lens is perfect for wedding photographers who want the extra focal length without overloading their gear bags. It’s a great portrait lens, too, and it focuses as close as 3.22 feet for those detail shots. If you’re a little hesitant about shelling out $2,500, rent the lens first. (And if you’re looking for a good prime, as we were going to press, Sony announced the development of an FE 400mm f/2.8 GM OSS lens).

Theano Nikitas has been covering the photography industry for over 20 years.