Fstoppers Reviews the Sony FE 100-400mm f/4.5-5.6 GM OSS Lens

Sony’s longest reaching zoom lens for Alpha mirrorless cameras, the FE 100-400mm f/4.5-5.6 GM OSS, offers versatile shooting possibilities with an extra emphasis on image quality.

Build

Inside the FE 100-400mm there’s 22 elements in 16 groups, 2 of which are extra-low dispersion and 1 Super ED element. The front element has a flourine coating to easily wipe away dust and repel water. The nine-bladed aperture is about par for the course for creating circular out of focus elements.

Moving to the outside, the telephoto lens has a light gray finish with painted on markings. Four switches on the lens control AF/MF, focus range, SteadyShot on/off, and OSS mode selection (mode 1 is for general shooting, while mode 2 is for panning shots). There are three focus hold buttons on the barrel between the zoom and focus rings. Buttons are located for shooting in either landscape or portrait orientation. The operation of the focus hold buttons can be customized in the camera menu settings. My wish here is for Sony to add in the ability to record and recall focus distances with these buttons.

The lens uses 77mm filters attached to the front, and the lens hood has a sliding window built in for easy access to adjust variable filters such as circular polarizers. Another neat trick is the ease of removing the tripod foot. Simply untwist the lock and press a release button to slide it off. The foot is easy to pack away since it isn’t the entire collar coming off.

The FE 100-400mm focus ring moves very smoothly. It has a great tension curve for precision while barely nudging it, while still allowing for fast sweeping across great focal changes. This is down to preference of the focus by wire system though.

The zoom ring features its own tension ring for controlling the smoothness or tightness characteristics. Unfortunately, the tight setting still allows the lens to creep while walking around. I wish they would have added a third setting, a zoom lock, to the tension ring.

Performance

Marked as a G Master lens, Sony is telling us that they believe this is the pinnacle what a consumer 100-400mm telephoto lens can be today. The resulting images from using this lens have excellent sharpness and clarity throughout the zoom range. It’s really refreshing to not have to be wondering where I am in the zoom range so that I don’t go too far into degradation territory.

One of the things I do have to pay attention to while zooming, however, is the aperture. As a variable aperture lens, I can’t get the full f/4.5 aperture at 400mm like I can while at 100mm. Regardless of where in the zoom range I am, stopping down at least a tiny bit will improve sharpness from good to great. And depending on what’s being photographed, the higher f-stop numbers of this lens may mean backgrounds aren’t going to be knocked out as much as wanted. Photographing horses jumping, for example, left me wishing for greater out of focus separation between the subject and background. Other subjects that I could get closer to physically before filling the frame at 400mm resulted in some stunning bokeh, however. The capability is there, it’s just harder to achieve if photographing sports and such unless you are very close to the action. I guess what I’m trying to say is that 100-400mm f/4.5-5.6 as a sports lens is good for documenting an event, but not for creating the prettiest of photographs.

The somewhat slow 100-400mm certainly relies on Optical SteadyShot and the good high-ISO quality of newer generation Alpha cameras to reach correct exposures, especially indoors. Many of my photos with this lens are above ISO 1600. For a camera like the monster a9, that’s as good as calling it ISO 100, but it’s something to bear in mind.

When the FE 100-400mm f/4.5-5.6 GM was first announced, I questioned if the FE 70-200mm f/2.8 GM plus 2.0x teleconverter would make for a more versatile setup; better speed and a narrower depth of field from 70mm to 200mm, and the reach to 400mm at f/5.6 when needed. Of course, the downside to this is the autofocus performance and image quality hit with the teleconverter. I have used the 70-200mm GM with 2.0x teleconverter in the meantime and the image quality hit is noticeable. Shots with the 100-400mm at 400mm though are crisp. The autofocus also never slouches with adequate light. This lens features a dual autofocus actuator so that the heavier front elements and rear elements can simultaneously move very quickly.

The 100-400mm GM is also compatible with the FE 1.4x and FE 2.0x teleconverters with a one stop and two stop additional loss of light respectively.

What I Liked

• Pairing the FE 100-400mm with the Sony a6500 crop-sensor camera is one of my favorite combos I’ve used on nature hikes. For the photo power I get, it’s a worthwhile carry.
• The sharpness is excellent throughout the zoom range. No worries about rocking it almost exclusively at 400mm.
• Minimum focusing distance of just 3.22 feet means extension tubes for closeup near-macro photography isn’t necessary.

What I Didn’t Like

• The zoom creeps and there’s no way to lock it down.
• Depth of field for sports wouldn’t knock out backgrounds enough for my liking.
• Focal length and variable aperture. I’d wager that most people buying this are getting it because it’s the current longest option in the FE lineup, but it’s still not that long. It would have been great to see Sony take the idea of Nikon’s 200-500mm f/5.6 and one-up it in some regard while dominating it in optics; Slightly better constant aperture?; More range?; Smaller package?

Conclusion

Now that the this lens has been out for over a year, it may be worth waiting and keeping an ear to the ground to see if any new developments are coming along (depending on what you are looking for in a telephoto). Now that more third-party companies are getting on board with E mount, we might see a more affordable native 150-600mm lens from Sigma or Tamron any day now, or someone smart taking notes from Nikon’s 200-500mm f/5.6. If you are looking at the FE 100-400 GM for what it is, and not because it happens to be the longest in the lineup right now, then I don’t think you will be disappointed with its image quality. It’s an excellent telephoto lens that is only held back by its aperture.

The Sony FE 100-400mm f/4.5-5.6 GM OSS is available now for $2,498.