Sony FE 50mm f/2.5 G (SEL50F25G) lens
The FE 50mm f/2.5 G is the final member of a trio of compact prime lenses announced by Sony in late March 2021, and it’s the pick of the trio when it comes to overall performance and versatility.
It produces nice sharp images across the frame with few or no visible artefacts and has a better-than average set of controls. It’s also Sony’s first compact 50mm full-frame mirrorless lens with both a de-clickable aperture ring and a programmable function button.
The FE 50mm f/2.5 G (SEL50F25G) lens is the final member of the trio of compact prime lenses announced by Sony in late March, 2021. It shares many features with its siblings, particularly the FE 40mm f/2.5 G (SEL40F25G) lens. All three lenses are much the same size and weight and all have similar weather-resistant sealing with fluorine coatings on their front elements to make them easy to keep free of grime. The 50mm and 40mm lenses are supplied with the same lens hood, which is outlined in our review of the FE 40mm f/2.5 G (SEL40F25G) lens.
Angled view of the FE 50mm f/2.5 G (SEL50F25G) lens without the supplied lens hood. (Source: Sony.)
The optical design of this lens (shown below) is similar to the SEL40F25G, consisting of nine elements in nine groups. However, there are two aspherical elements, with the addition of an extra-low dispersion element to suppress axial chromatic aberration.
This diagram shows the positions of the exotic glass elements in the optical design of the Sony FE 50mm f/2.5 G lens. (Source: Sony.)
The iris diaphragm has seven blades, which are curved to produce a near circular aperture as the lens is adjusted, creating pleasing bokeh quality. It can create 14-pointed sunstars at bright, specular highlights when the lens is stopped down to f/22, the minimum aperture.
Autofocusing is driven electronically by a linear motor, which also takes over in manual focus mode to provide a response in which the angular turning of the ring corresponds closely to the ‘natural’ feel of manual focusing. All focusing is internal, enabling this lens to be used with 49 mm screw-in polarising and graduated filters.
The aperture ring can be de-clicked to allow smooth, silent aperture readjustment during video recording.
Who’s it For?
The SEL50F25G is a significantly smaller and lighter and much more affordable standard prime lens than the faster FE 50mm f/1.2GM lens we reviewed recently. It is also an excellent performer, as shown in our test results below. We’ve nominated it for an Editor’s Choice because it currently represents the best value for money in the standard 50mm prime lens category for owners of Sony’s full frame cameras. It’s also arguably the most versatile of the lenses in the Sony trio.
It’s fast enough to be used for low-light photography, thanks to the effective IBIS in Sony’s α7 and α9 cameras and usable for indoor portraiture. As mentioned, all three lenses in the series are small and light enough to be easy to carry. They will also work well when mounted on gimbals and drones.
The 50mm focal length is probably the most versatile of the trio since it covers a similar field of vision to human eyes. This means the resulting photographs will capture the same perspective as we see and appear natural looking.
Build and Ergonomics
Physically, the FE 50mm f/2.5 G lens is almost identical to the FE 40mm f/2.5 G. It is also made mainly from aluminium alloy, with an engraved Sony logo and focal length designation on the barrel – the main distinguishing feature – plus threading that accepts the same 49 mm filters.
At the front of the lens barrel is the focusing ring, which is 8 mm wide and entirely covered with moulded ridging. Since focusing is driven from the camera, this ring turns through 360 degrees when power is off.
Roughly 2 mm behind the focusing ring is the aperture ring, which is marked in increments starting at f/2.5 on the right, followed by f/4 then with one-stop gaps to f/22 on the left, which click-stops at 1/3-stop intervals. A red ‘A’ mark beyond the f/22 setting denotes the auto aperture setting. It takes effect seamlessly when the camera is set to the P and auto shooting modes.
Side views of the FE 50mm f/2.5 G lens showing the locations of its controls. (Source: Sony.)
Behind the aperture ring is a 10 mm wide section of the lens barrel that carries the programmable focus button and AF/MF slider switch around the left side of the barrel and the click On/Off switch around to the right. The white index line for the aperture settings is located on this band, along with the 50 an G branding logos.
The barrel then slopes inwards and extends for another 10 mm section, which carries the index mark for mounting the lens on the camera plus additional branding data. The solid metal mounting plate is surrounded by a thin rubber gasket that seals the joint against ingress of moisture and dust.
Performance-wise, the FE 50mm f/2.5 G lens is the pick of the trio. We found it delivered resolution that was above expectations for the 24-megapixel sensor in the Sony α7 II camera used for our Imatest tests across the full image frame with JPEG files. Even higher resolution was recorded in ARW.RAW files that had been converted into 16-bit TIFF format with Adobe Camera Raw, our preferred raw file converter.
Resolution remained relatively high across the aperture range from wide open at f/2.5 through to about f/7.1 when diffraction began to take a gradual effect. The graph above shows the results of our tests on JPEG files.
Lateral chromatic aberrations in JPEG files recorded with all in-camera corrections disabled were well down in the low band, as shown in the graph of our test results above, in which the red line marks the boundary between ‘negligible’ and ‘low’ CA. We found no signs of coloured fringing in either JPEGs or raw files in our test shots and the in-camera corrections would generally correct any potential problems.
Vignetting could be seen in shots taken with apertures between wide-open at f/2.5 and about f/4. But we found few signs of rectilinear distortion, as expected. Both issues are capably handled by the in-camera corrections in Sony cameras so neither is a serious problem.
The review lens handled backlit subjects quite well and resisted flaring under most conditions. Flaring could be forced by pointing the camera at a bright light source but only occurred when the source was within the frame. When it was outside the frame, flare was rare thanks to the effective lens hood. Sharp 14-pointed sunstars were possible at f/22, albeit associated with the risk of flare artefacts.
The minimum focus distance of between 31 and 35 cm is adequate for close-ups of larger flora and fauna. As usual, bokeh in wide-aperture shots is influenced by background lighting. We noticed some outlining around brighter highlights in backlit close-ups and one example showed a solid circle at a specular highlight point.
Autofocusing performance was similar to the FE 40mm f/2.5 G lens, which is to be expected since they use the same technologies. Like that lens, the FE 50mm f/2.5 G lens suffers from slight focus breathing with the image increasing in size a little as it is focused more closely. But we doubt this would be problematic for most potential users.
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Picture angle: 32 degrees
Minimum aperture: f/22
Lens construction: 9 elements in 9 groups (including 3 aspherical elements)
Lens mounts: Sony FE
Diaphragm Blades: 7 (circular aperture)
Weather resistance: Yes; dust and moisture resistant
Focus drive: Linear motor with internal focusing
Stabilisation: Relies on IBIS in Sony’s cameras
Minimum focus: 35 cm (AF), 31 cm (MF)
Maximum magnification: x 0.18 (AF),x 0.21 (MF)
Filter size: 49 mm
Dimensions (Diameter x L): 68 x 45 mm
Weight: 174 grams
Standard Accessories: Front and end caps plus ALC-SH166 lens hood
Distributor: Sony Australia; 1300 720 07
Based on JPEG files recorded with the Sony α7 II camera.
Based on RAW-RAW files recorded simultaneously and converted into 16-bit TIFF format with Adobe Camera Raw.
All test shots taken with the Sony α7 II camera.
Vignetting at f/2.5.
ISO 200, 1/60 second at f/14.
Crop from the above image magnified to 100% showing little evidence of coloured fringing.
Close-up at f/2.5, 1/1000 second at ISO 100.
Backlit close-up at f/2.5, 1/1600 second at ISO 100.
Backlit close-up at f/2.5 showing circular rendition of specular highlights; ISO 100, 1/320 second.
Sunstar with flare artefacts; ISO 100, 1/250 second at f/22.
Forced flare; ISO 200, 1/60 second at f/18.
ISO 125, 1/60 second at f/11.
ISO 100, 1/100 second at f/8.
ISO 200, 1/60 second at f/9.
ISO 250, 1/60 second at f/8.
ISO 100, 1/640 second at f/3.2.
ISO 250, 1/80 second at f/8.
ISO 250, 1/60 second at f/11.
ISO 100, 1/100 second at f/9.
RRP: AU$999; US$599
- Build: 8.9
- Handling: 8.9
- Image quality: 9.0
- Autofocusing: 8.9
- Versatility: 8.9