The name Carl Zeiss has become synonymous with impressive lens sharpness for some time, and the 16-35mm continues that trend. I found the 16-35mm to be a very impressive ultra-wide zoom, with high image sharpness at the vast majority of settings. Central sharpness is very high straight from f/4 at the wide and middle of the zoom range, and this continues into the borders for the most part.
At all focal lengths, stopping the lens down to f/8 or so yields extremely good edge to edge sharpness and even good corner sharpness, which is quite difficult to achieve in an ultra-wide zoom. Click on the image to the right, then click on the green arrow at the bottom to view the image at full size. While falling short of the very best wide-angle prime lenses, the 16-35mm is among the sharpest ultra-wide zoom lenses I’ve had the chance to use. The only place the lens falters is wide open towards the end of the zoom range, especially at closer focus distances, where the lens produces only average resolution. Stopping down at 35mm is advisable for maximum sharpness.
Bokeh isn’t often discussed much in the realm of ultra-wide angle lenses, but being a full-frame lens at f/4, the 16-35mm is capable of blurring the background throughout the range when shot wide open, especially towards the long end of the zoom.
Bokeh on the 16-35mm is surprisingly nice, with a generally smooth rendering of out of focus areas with evenly lit specular highlights. I have to say that the lens produced far nicer bokeh than I was expecting, which was a very pleasant surprise. One thing to note is that the aperture stops down slightly at the wide end, even if wide open, in order to keep the lens at a constant f/4 aperture. As such, a hint of the 7-sided aperture can be seen in the specular highlights when shooting at f/4 and 16mm.
Color, Contrast and Chromatic Aberration
The Zeiss 16-35mm f/4 produces images with that rich Zeiss color and contrast that the brand has become known for. Images have pop and clarity throughout the range, with only a minor falloff in contrast towards 35mm. Overall, the rendering is beautiful for landscape and architecture shooting, which will make up a large portion of many shooters uses for the lens.
In Chromatic Aberration control, the lens does fairly well, producing unobjectionable CA at the wide end and only moderate CA at the long end of the range, which is exacerbated when stopping down. Still, the CA can be corrected with modern postprocessing tools with relative ease.
Distortion, Vignetting and Flare
The 16-35mm f/4 OSS has fairly typical lens distortion for an ultra-wide zoom, with pronounced barrel distortion at the wide end and moderate pincushion distortion at the long end. Fortunately, distortion profiles are automatically applied to JPEG images and Lightroom has a built-in profile for the lens to correct the distortions for RAW files as well. The lens is sharp enough that the distortion correction doesn’t seem to affect edge resolution in any major way.
The 16-35mm also performs quite well against bright light, with minimal loss in contrast and minimal ghosting as well when the sun is included in the frame. Vignetting is fairly low at wide apertures and essentially gone by f/5.6.
Overall image quality is excellent, with only some distortion and a bit of CA to keep it from being flawless. I can’t really ask much more for an ultra-wide zoom lens.