Samyang 12mm F/2 NCS CS

This Samyang is a manual-focus 12mm prime designed for APS-C mirrorless cameras. Mount versions include Samsung NX, Canon EF-M, Fujifilm X and Sony E. Choose the version made for your camera. Introduced in 2014, the design suits interiors, architecture and landscapes where a wide view is useful.

The f/2 maximum aperture is useful to consider for dim interiors or the night sky. The main trade-off is manual focus. Check how clearly your camera displays fine detail and which focus aids it offers, especially if subjects move towards or away from you.

The Samsung NX version weighs 8.3 oz (235 g) and measures 2.03 in (51.6 mm) long and 2.85 in (72.5 mm) across. Other mounts differ in weight and length. Allow room for the hood and caps when packing. Screw-in filters must match the 67mm front thread.

The 12mm focal length gives a wide view on APS-C. How much of a room or building fits depends on your position and the scene. Moving close to a rock or doorway makes it larger relative to the background. Check the frame edges for unwanted objects and foreground distractions.

Closest focus is 0.7 ft (20 cm), measured from the sensor. This range can help place a flower or small detail in the foreground. The clearance ahead of the lens is shorter than the focus distance. Leave room for light and avoid shading the subject with the camera.

The f/2 maximum aperture admits more light than a smaller opening. At a given shutter speed, it can allow a lower ISO in dim interiors or evening streets. For stars, check focus on a magnified view if the camera offers one. Test the exposure time for the amount of star movement you want.

Depth of field depends on aperture and focus distance as well as focal length. A near foreground and distant buildings may need a smaller aperture to appear sharp together. Choose the focus position deliberately and inspect both parts of the scene. A wide view does not remove the need for accurate focus.

There is no image stabilisation in the lens. A camera with body stabilisation can help with shake. Firm support helps during long exposures of still scenes, but passing people and wind-blown plants can continue to move. Choose shutter speed for the subject as well as your own hold.

The lens has no weather sealing. Keep it sheltered from rain and blowing sand, and protect the open mount during lens changes. Remove loose grit before wiping the front glass. Keep both ends capped when the lens is off the camera.

The 12-element, 10-group design includes one aspherical element, one hybrid aspherical element and three ED elements. Aspherical surfaces help correct distortion and spherical aberration. ED glass helps reduce coloured fringes along high-contrast edges, such as branches against bright sky. Their presence does not establish measured image quality.