Optical quality
Image: The inner area marks out the frame coverage when using the APS-C format, while the entire image is what has been recorded at the full-frame format
For this test I have taken a comprehensive range of images, covering the range of apertures and focus distances with both full-frame and APS-C format.
Centre sharpness is excellent with the Samyang 24mm f/1.4, especially when using apertures between f/4 and f/11. There is a minor drop off in resolved detail at the maximum and minimum aperture settings, which is standard for any lens. Impressively, though, detail is crisp, even in the corners, which is testament to the edge-to-edge quality of the glass.
I would avoid using the f/1.4 aperture. In this setting, it is difficult to achieve any sort of sharpness in the frame, with a soft glow around all areas, including the area in focus. Vignetting is pronounced, and chromatic aberrations (red and green ‘fringing’) are a little distracting across the entire frame. Drop down to f/2 and vignetting is significantly reduced and it is all but gone at f/2.8. Likewise, at f/2.8 fringing is reduced in the centre of the frame, although it is still present in particular situations such as backlit tree branches against a bright sky. In fact, without using chromatic aberration correction post-capture, fringing can be an issue all the way to f/8.
As expected from a wideangle lens, barrel distortion is obvious under the controlled studio setting and for scenes that include structures such as buildings. The lens is also not particularly flattering for portraits, but this focal length is not really designed for such use. In a landscape image, barrel distortion is not distracting.
The quality of the out-of-focus areas is, on the whole, pleasant, although in very specific situations, such as backlit gaps between the leaves in a tree, the bokeh can be a little poor up to f/2.8, with an orb effect. However, this is a very specific situation that is unlikely to crop up often in everyday shooting. Landscape photographers who use a ‘extensive’ depth of field are unlikely to ever see this effect because it is not present at apertures of f/4 and above.
The images show a small section of our resolution chart. All the images in this test were taken with the Samyang 24mm f/1.4 ED AS UMC lens and a Nikon D600, which has a full-frame, 24.3-million-pixel sensor.
