Sony FE 50mm f/2.5 G review

Within a short space of time, Sony has released two 50mm ‘extremes’. The Sony FE 50mm f/1.2 offers a maximum aperture many believed was not possible with the Sony E-mount, whereas this Sony FE 50mm f/2.5 is a whole two f-stops slower and (subject to a bit more research) perhaps the slowest 50mm mainstream lens currently available, outside of macro lenses.

But the FE 50mm f/2.5 is also extremely small, extremely light and extremely practical. It can go places where you just wouldn’t take a bigger lens. With a lens this size you can shoot all day without getting arm-ache, and you can use your Sony A7 on a gimbal without popping a bicep in the process.

There are other 50mm lenses in the Sony range, including the Planar T* FE 50mm F1.4 ZA (which we think the new Sony 50mm f/1.2 effectively replaces), which is a real monster, and the more affordable FE 50mm F1.8, which is still significantly larger than this new lens.

• Read our full reviews of the other two lenses in this family:

• Sony FE 24mm F2.8 G review
• Sony FE 40mm F2.5 G review

Specifications

Format: Full frame
Focal length: 50mm
Maximum aperture: f/2.5
Optical construction: 9 elements in 9 groups
Minimum focus distance: 0.35m
Filter size: 49mm
Dimensions: 68mm (W) x 45mm (D)
Weight: 174g

Key features

If you’ve been reading about the other two lenses in Sony’s trio of compact primes – the FE 24mm f/2.8 G and the FE 40mm f/2.8 G – you’ll know what’s coming. All three are effectively the same size and weight and even use the same 49mm filters. All three have aperture rings which can be ‘de-clicked’ for video use via a switch on the lens barrel.

The FE 50mm f/2.5 G is the ‘longest’ of the three new lenses, and while a maximum aperture of f/2.5 might sound very tame by today’s standards, it’s still faster than even a pro zoom lens, while being a fraction of the size and cost. 

Build and handling

This lens’s size is one of its key features. As we’ve noted in the reviews of the other two lenses in this new family, it completely changes the balance of Sony’s A7 cameras. These are remarkably compact full frame cameras even by today’s standards, but this means they are easily unbalanced by big heavy lenses – and many Sony FE mount lenses are big and heavy, especially the zooms. The grip on a Sony A7 is really only tall enough for three fingers, and when you put a heavy lens on the front, that puts a lot of leverage on your hand and forearm.

So it’s not just about this lens’s handling on its own that’s significant, but what it does to the balance of the camera. We like it a lot for that reason alone – but this lens is also very well made. The aperture ring is very firm and positive, yet super-smooth when ‘declicked’ for video.

But as we’ve noted with the other lenses in this trio, there is no focus distance scale. These seem to be going out of fashion on modern mirrorless lenses, which is very disappointing for those of use who still like to work with depth of field.

Performance

Performance-wise, this lens is just terrific. The dual linear AF motors do their work silently, smoothly and quickly. There no stabilisation, but all current Sony A7 (and A9) cameras have in-body stabilisation anyway.

In real-world shooting the optical performance looks every bit as good as that of the FE 40mm f/2.5 G, with no distortion either in the camera JPEGs or in uncorrected raw files – though the lab results show the FE 50mm doesn't quite match the edge sharpness of the 40mm at wider apertures. The differences are so small as to be hard to see, however. This lens might be compact but this does not appear to have compromised its optical performance at all, which is quite stellar.

Lab tests

We run a range of lab tests under controlled conditions, using the Imatest Master testing suite. Photos of test charts are taken across the range of apertures and zooms (where available), then analyzed for sharpness, distortion and chromatic aberrations.

We use Imatest SFR (spatial frequency response) charts and analysis software to plot lens resolution at the centre of the image frame, corners and mid-point distances, across the range of aperture settings and, with zoom lenses, at four different focal lengths. The tests also measure distortion and color fringing (chromatic aberration).

Sharpness:

Centre sharpness is sensational, especially between f/2.8 and f/5.6. However, our sample lens didn't quite match the centre sharpness of the FE 40mm f/2.5 G, and the same applies to mid-frame and corner sharpness, which is significantly less than you get from the 40mm. Even so, levels of corner sharpness from the 50mm are still very good, especially once you stop down to f/5.6.

Fringing:

As with the FE 40mm f/2.5 G, fringing is a little more pronounced at larger apertures, but is still easily low enough to be unnoticeable in real-world shooting scenarios. Once you stop down to f/4, fringing is as good as non-existent - a very impressive result.

Distortion: 0.83

A negative score indicates barrel distortion, a positive score pincushion. A score of zero signifies no distortion.

The lens produces minor pincushion distortion, but certainly not enough to noticeable in most shooting scenarios. Once lens profiles are available, even this mild distortion will likely be straightened out by raw processing tools like Adobe Camera Raw.

Verdict

You have to decide if 50mm is a focal length you like, and if a maximum aperture of f/2.5 is enough. We can’t mark this lens down for either. That f/2.5 maximum aperture is a result of the compact lens design, and for us the remarkable downsizing in this lens is easily worth the loss of light-gathering power. You have to decide which is most important for you – portability or specifications. The modest specs do make this FE 50mm f/2.5 G look quite expensive, but don’t forget you are also getting an aperture ring with a declicking mechanism, dual linear motor AF and first rate optical performance.

• Pre-order the Sony FE 50mm F2.5 from Wex
• Pre-order the Sony FE 50mm F2.5 from Park Cameras

Read more:

• Best Sony lenses
• Best Sony cameras
• Best 50mm lenses
• Sony FE 24mm F1.4 GM
• Sony FE 35mm F1.4 GM