Sony 100-400mm F4.5-5.6 OSS GM

The Sony 100-400mm GM is a super telephoto lens for full frame E-mount cameras and currently the longest native zoom lens available for this system. GM is short for G Master, Sony’s premium lens line. So is it just an expensive piece of glass or a masterpiece? Let’s find out if Sony is able to match the expectations.

Specifications

  • Focal length: 100 – 400mm (4x zoom)
  • Format: 35mm full frame
  • Lens elements / groups: 22 / 16
  • Min. focus distance: 98cm
  • Max. magnification: 0.35x
  • Aperture: 9 rounded blades
  • Autofocus: linear motor, Direct Drive SSM
  • Stabilization: OSS
  • Coating: Sony Nano AR
  • Resistance: dust and moisture
  • Filter thread: 77mm
  • Dimensions: ~20.5 x 9.4cm
  • Weight: 1395g
  • Country of origin: Japan
  • MSRP: 2900€

There is a lens hood, a carrying case and a tripod collar included in the box.

 

 

Build quality

As expected at this price point, build quality is very high, nothing wiggles or feels cheap. The surface coating seems to be quite scratch resistant.

One thing though put me off a little bit: the weird smell, a mixture of glue and mildew. I checked the lens for dirt, moisture or other damage, but couldn’t spot any, so I assume it must be the kind of plastic that they used. Not a big deal since it goes away after some time, but nevertheless not something you would expect in this price class.

The zoom and focus rings are smooth to turn. There’s a zoom torque adjustment ring for the zoom function. A nice feature, although I personally would have preferred a simple lock button. The lens does creep in the “smooth” setting, but is held in place once the ring is set to “tight”.

The lens is dust and moisture resistant (although not guaranteed).

In contrast to most other current Sony lenses, the 100-400mm GM is made in Japan.

Mechanical quality rating: 9/10

 

Features and versatility

The 100-400mm focal length range is very versatile, perfect for wildlife photography.
The aperture range goes from F4.5 at the wide end to F5.6 at the long end. Note that the aperture closes down pretty quickly and already reaches F5.6 at 200mm. This is not a partcularly fast lens, but sufficient for most cases.
Even though this lens is considered lightweight and compact in its class, it is still a large and heavy lens. It handles ok on the Sony A7III.

100-400mm on the Sony A7III
100-400mm fully extended on the Sony A7III

There are numerous buttons and switches on the lens: 3 custom buttons, an AF/MF switch, a focus limiter and a OSS on/off as well as OSS mode switch.

The lens also offers optical stabilization, which proved to be excellent in my tests. I find it quite easy to get sharp shots at 1/20th at 400mm, that’s about 4 stops better than what the 1 over focal length rule of thumb suggests.

The AF is blazingly fast and noiseless.

One of the greatest features of this lens is its minimum focus distance of just 98cm at 400mm. This allows for a maximum magnification of 0.35x (~1:2.9), which is already considered macro territory.

Features and versatility rating: 9/10

 

Image quality

According to DXO Mark, the Sony 100-400mm GM is one of the sharpest zoom lenses ever produced:

DXO Mark lens rating

My first impressions concur with these results: The lens is incredibly sharp across the frame and zoom range. Unlike most telezoom lenses, the Sony 100-400mm barely shows any signs of sharpness reduction towards the long end. The amount of detail you can get at 400mm is simply amazing.

Let’s start with the sharpness at 100mm:

At 200mm:

At 400mm:

Note that the slight hazyness is due to atmospheric effects and not caused by the lens! The target subject for this test was about 1 mile away.

In terms of aberrations, there is not much to complain about. Laterial CA and LoCA are barerly visible and even near the closest focus distance the image quality is excellent.

close focus at 400mm F5.6
crop from the image above (click to see full resolution)

 

crop from a photo (not shown here) to show the amout of LoCA at 400mm F5.6

Distortion and vignetting are nothing to be worried about either and flare restance seems to be solid.

bokeh at 400mm F5.6

Out-of-focus background blur is quite pleasant and smooth. Bokeh balls appear uniform without noticable artifacts (apart from mechanical shading, obvously).

bokeh balls at 100mm F4.5
crop from the image above: bokeh balls

 

Image quality rating: 10 / 10

 

Comparison

Vs the Tamron 100-400mm: The Sony has substantially better image quality, particularly towards the corners. Autofocus is night and day compared to the Tamron 100-400, which is not surprising since there is no native version for Sony E-mount yet. Also, the build quality and the amount of switches and buttons on the lens is much better on the Sony lens.

 

Sony 100-400mm with Rolan Pro lens coat

Summary

For:

  • excellent build quality, weather resistant construction
  • versatile zoom range
  • fantastic image quality, high resolution accross the frame at all focal lengths
  • relatively lightweight and compact in its class
  • optical stabilization
  • very low chromatic aberrations
  • fast and silent autofocus
  • short min. focus distance (suitable for macro)
  • several buttons and switches on the lens
  • lens hood, carrying case and removable tripod collar included

Against:

  • aweful smell (goes away after some time)
  • no arca swiss compatible tripod collar
  • price (MSRP 2900€)

An exceptional lens with a premium price tag. Not much more to add to that. Highly recommended!

Rating:  9.5/10    essential!

Value:  4/10    (reviewed at 2050€)

Link to Amazon.de.

Sony 100-400mm with Rolan Pro lens coat

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