Owing to its minimalist design, operating the lens in the field is a largely simple and intuitive process. Autofocus in single autofocus mode (AF-S) is precise and fast, on par with other native Sony and adapted Canon lenses I’ve tested. I did, however, notice that in continuous autofocus mode (AF-C), the lens would occasionally hunt and be unable to lock on to a stationary subject. This may be due to a combination of the extremely wide field of view and very large depth of field. Indeed, critically focusing the Batis 18mm manually is almost impossible, even with magnified live view and focus peaking turned on. The details are so small and the depth of field so large that it’s difficult to tell when something is at its sharpest. That said, the hybrid autofocus of the A7RII, when in AF-S mode, did a good job and I have yet to see any misfocused images. The Batis 18mm is not image stabilized, as few lenses are at this focal length. But the in camera stabilization in the Sony took care of any camera shake on the few handheld shots in this test.
The lens is surprisingly light and compact for an ultra-wide. It feels right at home on the diminutive A7RII body. As a system, it’s well balanced and easy to carry around. Having a maximum aperture of f2.8 certainly helps with size and weight. Unfortunately, the maximum aperture is a bit slow for astrophotography, where f2 or even f1.4 lenses are preferred. The front lens element doesn’t protrude very far and 77mm front filters can be used on this lens. It’s best to stick with thin profile filters to avoid vignetting. With the Batis 18mm, Zeiss has struck a nice balance between focal length, aperture, size, weight, and the ability to use front filters. The lens is a pleasure to use.
Like the rest of the Batis lens line, the 18mm is weather sealed and should handle light rain admirably. As you can see by some of the sample photos, the weather sealing came in handy during my time with the lens. Neither the lens nor the camera showed any adverse effects after spending several hours out in a light, but constant drizzle. The one cautionary tale is that even the smallest water drops on the lens will show in your images because of the tremendous depth of field at such a short focal length. For landscape work with an ultra-wide lens, having a prominent and very close foreground is paramount. This means stopping down to increase the depth of field yet further. While I kept the lens cap on as long as possible and used an umbrella whenever a hand was available, a few images still showed the blurred outlines of tiny rain drops.