Review: Sony SEL50F18 50 mm f/1.8 OSS


The Sony SEL50F18 is a 50 mm f/1.8 normal lens for APS-C E mount cameras, where it acts as a shot tele. It was one of the first primes in Sony’s E mount line-up, released in late 2011.

The SEL50F18 is a light but not very compact lens with excellent build quality and great handling on the NEX. It comes with a long clip-on circular lens hood. Autofocus is reasonably fast but does not impress, even when using hybrid-AF. In DMF mode with manual focus override, the lens reacts very precisely to your input. The effective focal length of 76 mm on APS-C cameras makes the SEL50F18 an excellent, no-worries lens for every day use and the occasional portrait.

 

Condition of my copy

Optics: Excellent. No dust, no scratches – new.

Mechanics: Excellent. Focus ring uniform and nicely damped, aperture clean and fast.

Exterior: Excellent. Like new.

 

Optical performance on NEX-5N / 5T

The following evaluation is based on uncorrected RAW images. Please keep in mind that all Sony E mount lenses are electronically corrected in camera (vignetting, distortion, CA) and JPEGs of these shots therefore look very different.

Notice: In the test charts, the left half of the picture was a little less sharp  than the right. This suggests either a slight decentering of the lens or a misalignment of the camera in relation to the chart.

The lens starts at f/1.8 with good center sharpness and only slightly soft corners. Going to f/2 gives minimally more contrast, but otherwise doesn’t change the image much. At f/2.8, corner performance improves visibly and central sharpness reaches very good levels. From f/4 to f/8, sharpness is outstanding across the whole frame. Diffraction starts lightly at f/11, is pronounced at f/16 and strongly softens f/22. Even the SEL50F18 can’t beat physics, after all.

There is a slight color cast visible on edges at f/1.8 and f/2, but stopping down clears it. From f/2.8 onwards, CAs are hardly visible, even at 200% magnification. An excellent performance.

Vignetting is about 1 stop at f/1.8 and f/2, hardly visible at f/2.8 and gone by f/4. The lens also exhibits a slight pincushion distortion of 0.7%. The effective T-stop at f/1.8 is T2.0 (-0.4 EV), which is okay.

How does it compare? Well, up to f/2.8, it’s ahead of all the vintage normal lenses – namely the MC Rokkor-PG 50 mm f/1.4. Ahead means that it is haze-free and offers a lot more contrast because it shows very little spherical aberration. Resolution actually isn’t that much higher. From f/2.8 on, there’s hardly any difference visible in the test charts between the Sony 50 mm and the best vintage primes in terms of sharpness and resolution. The nearly invisible CAs of the SEL50F18 are an advantage, though. I would also suspect that it delivers higher contrast in real life images up to about f/5.6. In conclusion, the Sony delivers sharp, contrasty and absolutely neutral images with the advantages of offering AF and image stabilization (OSS), which no vintage prime can give you. In return, you loose about half a stop of light compared to an f/1.4 and the ability of giving pictures that certain glow, which is possible wide open with fast vintage lenses.

 

Test charts

The following images are pixel-level crops from the test chart. They may appear scaled in your browser window. Click on them to view the crops in full size and cycle through them easily. For more info on the test setup, visit the details page.

 

Overview

Test chart overview

(Cropped areas marked in orange)

 

f/1.8

Sony SEL50F18 50 mm f/1.8 @ f/1.8

 

f/2.0

Sony SEL50F18 50 mm f/1.8 @ f/2.0

 

f/2.8

Sony SEL50F18 50 mm f/1.8 @ f/2.8

 

f/4.0

Sony SEL50F18 50 mm f/1.8 @ f/4.0

 

f/5.6

Sony SEL50F18 50 mm f/1.8 @ f/5.6

 

f/8.0

Sony SEL50F18 50 mm f/1.8 @ f/8.0

 

f/11

Sony SEL50F18 50 mm f/1.8 @ f/11

 

f/16

Sony SEL50F18 50 mm f/1.8 @ f/16

 

f/22

Sony SEL50F18 50 mm f/1.8 @ f/22

 

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