Part of Fuji’s original XF lens lineup launched alongside the X-Pro 1, the 18mm pancake prime has a bit of a reputation for being the weakest. The problem is this reputation really isn’t deserved. Sure it’s not quite as sharp across the frame as its 35 and 60mm siblings, but it’s a very different class of lens. What it offers is a really compact, wide view of the world with a bright f2 maximum aperture and crazy close focusing abilities. It can also produce some surprisingly nice bokeh, which is unusual for a wide angle lens. I’ve been shooting the 18mm f2 for several months – in fact it replaced my 18-55mm zoom as I prefer shooting primes and wanted something more compact. So far I’ve not been disappointed.
Sharpness in the center of the frame is really good throughout the range. For landscapes I find f8 is the sweet spot for across the frame sharpness. If available light won’t allow that then f5.6 isn’t much worse. Where corner performance is less critical I have no problem using it wide open or at f2.8 for when I need a hair more depth of field. For scenes where distortion is not disturbing, it’s worth using a 3rd party RAW processor that lets you disable the automatic correction applied by Lightroom, SilkyPix and the in-camera JPG engine. I find this makes the extreme corners a lot sharper. I use Iridient Developer which allows you to disable all automatic corrections, see the sample below for the difference it makes. Applying chromatic aberration correction is also important to get the most from this lens as even stopped down it’s quite pronounced in the corners. It would be nice of course if the lens was fully optically corrected, but then it would no doubt be a lot larger and more expensive, akin to Fuji’s 14mm prime. The trade off for price and size is a bit more work on your computer, but you can still get fantastic results.
The 18mm lets you focus extremely close to your subject, up to 18cm (~7″) which is both interesting from a compositional stand point and lets you experience the surprisingly nice bokeh this lens can produce when the depth of field is shallow enough. Nice bokeh and wide angles don’t usually go hand in hand, and this is an area where the prime handily beats the 18-55mm zoom at f2.8.
So in conclusion what the 18mm gives you is a versatile, sharp, tiny lens with nice bokeh. It does have its flaws, but all of them are correctable with post processing. Compared to Fuji’s other offerings, the 18mm definitely has an edge on the zooms that cover its focal length in terms of sharpness, size and bokeh. It may be outclassed by the 14mm, but it still wins on size and cost by a large margin.