Sony NEX E 20mm f/2.8 Pancake Lens Review

Sony E 20mm f/2.8 Pancake Performance

Sharpness in the centre of the image area just about reaches good levels at maximum aperture, with the clarity towards the edges not being far behind. Peak sharpness across the frame is achieved with the aperture stopped down to f/5.6. Here sharpness reaches excellent levels across the frame.

Resolution at 20mm

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 Sony NEX-5R using Imatest.

Chromatic aberrations are quite high at maximum aperture towards the edges of the frame. Here fringing just exceeds one pixel width, which is a level of fringing that will become visible around high contrast edges.

Chromatic aberration at 20mm

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 Sony NEX-5R using Imatest.

Falloff of illumination towards the corners of the frame is really quite pronounced. At f/2.8 the corners are 2.48 stops darker than the image centre and visually uniform illumination isn't achieved until the aperture is closed down to f/8.

Distortion is quite strong for a fixed focal length lens. Imatest picked up 2.44% barrel distortion during testing. Luckily the distortion pattern is uniform across the frame, which should make applying corrections in image editing software reasonably straightforward.

Contrast holds up well when shooting into the light and there are very few instances of flare, even in very harsh lighting conditions.

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