Conclusion

The Carl Zeiss Touit Distagon 2.8/12mm T* is the widest lens in the Fujifilm XF and Sony NEX line-ups, and is therefore worthy of attention from anyone interested in landscape and architectural photography. As well as offering a very wide angle of view, it's also a great lens in its own right, with virtually nothing to complain about apart from the high cost of ownership.

The Carl Zeiss Touit 12mm lens is remarkably sharp in both the image centre and at the edges throughout almost the entire aperture range. The fast maximum aperture of f/2.8 makes it easy to creatively throw the background out of focus, with the nine-blade iris diaphragm achieving some lovely bokeh effects for such a wide-angle lens. Vignetting is very well-controlled and chromatic aberrations are hard to find. There is some very slight barrel distortion, but given the ultra-wide-angle focal length its certainly nothing to worry about. The close-focus point of 18cm comes in handy when including foreground interest in the image, as you often do in landscape and architectural photography.

The Carl Zeiss Touit Distagon 2.8/12mm T*'s auto-focus system is a little hesitant on the Sony NEX-5R that we tested it on, with a slight delay before locking focus. It offers a generously wide focusing ring, and on the Fujifilm XF version a very welcome aperture ring which makes it quick, easy and precise to set this key element of exposure. We did miss having a focusing distance scale with depth-of-field markings, though, for easier zone-focusing. The overall build quality is excellent with a lens mount that's made of metal and, thanks to an internal focusing (IF) system, the front element and 67mm filter thread do not rotate on focus, which is very good news for those using polarisers and ND grads on a regular basis.

The main downside of the Carl Zeiss Touit Distagon 2.8/12mm T* lens is the price - at around £950 / €920 / $1,250 it's substantially more expensive than the closest Fujifilm and Sony lenses, and with 12mm being something of a niche focal length, you really need to be certain that you'll use it enough to justify the cost. For landscape and architectural photographers who want the widest angle of view and the best image and build quality, though, the Carl Zeiss Touit Distagon 2.8/12mm T* lens certainly won't disappoint.

Ratings (out of 5)
Design	4.5
Features	4
Ease-of-use	4.5
Image quality	5
Value for money	3.5