Sony FE 100mm f/2.8 STF GM OSS Review

Name: Sony FE 100mm f/2.8 STF GM OSS
Brand: sony

May 2, 2017 | Mark Goldstein |

Introduction

The Sony FE 100mm f/2.8 STF GM OSS is a new short telephoto prime lens for the Sony A7 full-frame E-mount compact system camera. It's the first Sony lens to incorporate a unique optical apodization lens element. This is similar to a neutral density filter which increases in density towards the edges, creating very soft, smooth bokeh effects in conjunction with the near-circular 11 blade diaphragm. It also features 13 elements in 10 groups including one aspherical and one extra-low dispersion element, built-in Optical SteadyShot image stabilization, and has a minimum focusing distance of 57cm with a maximum magnification of 0.25x. It has a manual aperture ring that can be de-clicked, an internal focusing mechanism which means the lens barrel doesn’t move, and is also dust and moisture resistant. The Sony FE 100mm f/2.8 STF GM OSS lens is available for around £1600 / $1500 in the UK and the US, respectively.

Ease of Use

Weighing in at 700g and measuring 11.8cm in length, the aluminium alloy bodied Sony FE 100mm f/2.8 STF GM OSS is about average for an f/2.8 full-frame 100mm lens. It's overall size complements a body like the Sony A7R II body that we tested it with, as shown in the photos below.

The Sony FE 100mm f/2.8 STF GM OSS lens mounted on a Sony A7R II

The Sony FE 100mm f/2.8 STF GM OSS lens alongside a Sony A7R II

Build quality is excellent, a relief given the price-tag. The Sony FE 100mm f/2.8 STF GM OSS has a sealed dust and moisture resistant design which makes it well-suited to life in both the field and the studio.

The Sony FE 100mm f/2.8 STF GM OSS lens has a metal lens mount. It accepts 72mm filters via metal threads.

Side of the Sony FE 100mm f/2.8 STF GM OSS lens

The Sony FE 100mm f/2.8 STF GM OSS has a round Focus Hold Button which keeps the lens locked to the current focusing distance, useful if you're auto-focusing and don't want the lens to try and find focus again. The preview function can also be assigned to this button through the camera's custom settings.

The Focus Range Limiter switch prevents the lens from hunting throughout the entire focusing range. There are two options - 0.57m-1.0m and 0.85m-infinity.

Front of the Sony FE 100mm f/2.8 STF GM OSS lens

Rear of the Sony FE 100mm f/2.8 STF GM OSS lens

The Sony FE 100mm f/2.8 STF GM OSS has a fairly wide and ridged focus ring. Manual focusing is possible by using the sliding focus ring to toggle between AF and MF. The lens utilizes direct drive SSM (Super Sonic Motor) motors to produce quiet and smooth focusing, making it well-suited to shooting video, with the overall lens length remaining constant during focusing.

The dedicated aperture ring has 1/3EV stops ranging from T/5.6 to T/22 and an Auto setting. A dedicated switch on the bottom-right of the lens barrel lets you select whether the aperture ring clicks into place at each aperture stop or rotates smoothly for silent operation during movie recording.

Front of the Sony FE 100mm f/2.8 STF GM OSS lens

Rear of the Sony FE 100mm f/2.8 STF GM OSS lens

The Sony FE 100mm f/2.8 STF GM OSS features optical image stabilisation, which together with the A7R II's own built-in stabilisation mean that we could successfully hand-hold the camera up to 4-4.5 stops slower than with a lens with no image stabilisation.

The Sony FE 100mm f/2.8 STF GM OSS lens in-hand

The Sony FE 100mm f/2.8 STF GM OSS lens with the supplied lens hood fitted

The Sony FE 100mm f/2.8 STF GM OSS lens is commendably supplied with both a soft case and a good quality plastic round lens hood.

Focal Range

At the 100mm focal length the angle of view is 24 degrees.

Sony FE 100mm f/2.8 STF GM OSS Field of view at 100mm

Focusing

The Sony FE 100mm f/2.8 STF GM OSS lens has a fairly wide focus ring. There are no hard stops at either end of the range, making it a little more difficult to set focus at infinity. Polariser users should be pleased that the 72mm filter thread doesn't rotate on focus.

When it comes to auto-focusing, the Sony FE 100mm f/2.8 STF GM OSS zoom is a fairly quick performer on the Sony A7R II that we tested it with, taking about 0.25 seconds to lock onto the subject.

We didn't experience much "hunting", either in good or bad light, with the lens accurately focusing almost all of the time, and it's also a quiet performer thanks to the direct drive SSM (Super Sonic Motor) internal focusing, making it ideal for movie shooting.

Chromatic Aberrations

Chromatic aberrations, typically seen as blue or purple fringes along contrasty edges, were not very apparent in our test shots, only appearing in very high contrast areas.

Light Fall-off and Distortion

With the lens set to its maximum aperture of f/2.8, there is some light fall-off in the corners, requiring you to stop down by at least 2 f-stops to prevent it.

There's some very slight barrel distortion evident at 100mm in the RAW files - the Sony A7/A7R II automatically and successfully apply corrections to the JPG files.

Sony FE 100mm f/2.8 STF GM OSS

Macro

The Sony FE 100mm f/2.8 STF GM OSS offers a minimum focusing distance of 57cm with a maximum magnification of 0.25x. The following example demonstrates how close you can get to your subject.

Sony FE 100mm f/2.8 STF GM OSS Close-up performance

Bokeh

Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc. In the Sony FE 100mm f/2.8 STF GM OSS lens, Sony employed an iris diaphragm with 11 rounded blades and a lens design that includes the unique optical apodization lens element, which has resulted in spectacular bokeh. We do realise, however, that bokeh evaluation is subjective, so we've included several 100% crops for your perusal.