Yongnuo 50mm f/1.8 Lens Review

Yongnuo 50mm f/1.8 Performance

At maximum aperture, sharpness in the centre of the frame is already very good, although clarity towards the edges of the frame is fairly poor. Stopping down improves performance across the frame, although the difference is more dramatic in the centre than towards the edges. Peak performance in the centre is achieved at f/4, where clarity is outstanding. Sharpness towards the edges takes a long while to catch up, only reaching good levels by f/8 and peaking with very good sharpness between f/11 and f/16.
 

 

How to read our charts

The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column.

The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple.

For this review, the lens was tested on a Canon EOS Mk III using Imatest.

Chromatic aberrations are well controlled, with fringing hovering around the 0.5 pixel widths towards the edges of the frame between maximum aperture and f/4. This level is low enough to cause few issues, even in very large print sizes, or with harsh crops from the edges of the frame.

How to read our charts

Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.

Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.

For this review, the lens was tested on a Canon EOS 5D MkIII using Imatest.

Falloff of illumination towards the corners is quite pronounced. At f/1.8 the corners of the image area are 2.54 stops darker than the image centre and stopping down to f/5.6 results in visually uniform illumination.

Barrel distortion is typical for a prime lens with a fast maximum aperture. Imatest detected 1.4% barrel distortion, which may become noticeable in images with straight lines parallel to the edges of the frame, but should pose few issues most of the time. The distortion pattern is uniform across the frame, so it should be relatively straightforward to correct in image editing software afterwards.

No hood is supplied with this lens. Even so, the front element is recessed and is reasonably well shaded as a result, so a hood may not be needed. Shooting into strong light sources, such as the sun, may result in a noticeable loss of contrast under certain circumstances. Strong light sources outside the frame may also cause flare.

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