The aperture ring of the new XF27mmF2.8 R WR features an easy-to-read scale. The user can see the set value at a glance without having to look through the viewfinder or at the camera's display. A lock function allows the aperture ring to be locked at the "Auto" position to prevent accidental adjustment while shooting. The XF27mmF2.8 R WR is also suitable for use in bad weather and adverse conditions. Seven seals protect the inside of the lens from splashing water and dust, and ensure its readiness for use in cold conditions down to minus 10 degrees Celsius. The focal length of the XF27mmF2.8 R WR is nearly identical to the diameter of the image circle required to fully cover the APS-C sensor (28.4mm). This allows for an ultra-slim lens with high image quality. The XF27mmF2.8 R WR is one of the smallest and lightest lenses in the XF series. It measures just 62mm in diameter and is exceptionally handy at just 23mm in length. It is also very light at around 84 grams, making it the ideal choice for situations that require the most compact equipment and the least amount of luggage. Despite its slim design, the optical construction of the new lens incorporates seven elements in five groups, including an aspherical lens to correct optical errors such as spherical aberration and distortion. Because of this construction method, the XF27mmF2.8 R WR offers high resolving power even when the aperture is fully open. The XF27mmF2.8 R WR features a powerful AF motor for fast and precise automatic focusing. Common aberrations when shooting close-up or distant subjects are effectively corrected by the five elements of the front lens group. High image quality is therefore guaranteed over the entire focus range.