4) Lens Sharpness, Contrast and Color Rendition
On the first day of trying out the Zeiss, I mounted it on my Nikon D3s and took a picture of my son Ozzy while he was watching TV. As he was sitting still, I moved the focus point on his right eye, set aperture to f/2.0 then started to move the focus ring until the camera set the image was in focus. I then snapped a picture and looked at the camera LCD:
Ozzy’s eye was in perfect focus and I got very impressed by the colors and the quality of the background this lens produced. Next, I zoomed in to 100% and saw this:
That’s one sharp manual focus lens!
Now let’s take a look at how the lens measured in my lab with Imatest software:
As you can see, the performance of the Zeiss 35mm is excellent. Center sharpness is very good even wide open, while the corners start out a tad weaker, but get much sharper by f/5.6 and beyond. Contrast and colors are superb as can be seen from other image samples posted in this review.
The bokeh on the Zeiss 35mm looks pleasant for a lens of this class and focal length. While depth of field is not as shallow as on the Nikon 35mm f/1.4G, background highlights look circular and soft, with a slightly visible edge. Nothing to worry about though, because this type of behavior is expected from a wide-angle lens, so there are no surprises here. Here is an example of bokeh shot at f/2:
Here is another shot at f/2:
Similar to other Nikon 35mm lenses I tested, the Zeiss Distagon 35mm f/2 has a heavy amount of vignetting at largest apertures, especially wide open at f/2.0. Take a look at lens vignetting properties, as measured by Imatest and compared to other 35mm lenses:
At maximum aperture, the Zeiss 35mm f/2 produces more vignetting than other lenses at f/1.4, reaching almost 3 EV in the extreme corners. As you stop down to f/2.8 vignetting starts to decrease and by f/5.6 onwards it is very subtle. Although this type of behavior is expected from large aperture lenses, especially when they are mounted on full frame cameras, vignetting on the Zeiss 35mm f/2 can be considered unusually high. However, this heavy vignetting does not bother me a bit – in fact, I actually like the way this lens renders images wide open. In addition, vignetting is reduced quite a bit when focusing at close distances, so the 3 EV results you see above are only seen when shooting at infinity. If you look at some of the images in this review that were shot wide open, it is the combination of clear colors and vignetting, which made images look more three dimensional and pleasant to look at in my opinion.
I have a feeling that Zeiss purposefully designed this lens to behave in such a way – moderate vignetting at close distances for portraiture and if one shoots at infinity, they would most likely stop down anyway…
Here is the worst case scenario of vignetting as illustrated by Imatest, at f/2.0 infinity focus:
7) Ghosting and Flare
The amount of flares and ghosting will depend on where you position the light source in the frame. Shooting directly at the sun, you will most definitely get some flares and ghosting if the sun is in the middle of the frame, as seen below. As you move the light source towards the corners, the size and length of ghosting/flares can get dramatically bigger, so take this into consideration when shooting outside. If you see a strong amount of ghosting and flares, try moving the light source in your frame to see where the effect is minimal and acceptable. Take a look at this shot of the Mesa Arch at f/13:
While Zeiss shows a minimal amount of ghosting and flares at largest apertures, stopping it down to f/8.0 and beyond can yield some nasty flares. Note the left bottom corner of the frame in the above shot, where you can clearly see a large orange blob that is taking almost half of the frame and changing the color of the rock. This is the worst case scenario – when an extremely bright and small source of light reflects off the internal lens elements. There are also some purple colors right under the star-shaped sun.
The coating on the Zeiss lens works great when the source of light is larger or slightly diffused though. Take a look at the following shot, with the sun behind the clouds:
As you can see, there is only one small ghost in the frame and no signs of nasty flares throughout the frame. Please note that both images were taken without any filters. Using UV and other filters can potentially introduce more flares and ghosting to your images.
Distortion on the Zeiss is moderate, very comparable to other 35mm lenses. Imatest measured barrel distortion of 1.25%, which is not bad for a 35mm lens, but definitely not great either, as it will translate to visible barrel distortion in images. In comparison, the Sigma 35mm f/1.4 Art has practically no visible amount of distortion.
If you use the latest version of Lightroom, it already comes with a lens profile for this lens and many other Zeiss lenses. Simply check “Enable Profile Corrections” in the Lens Correction sub-module of the Development module in Lightroom and all distortion + vignetting issues will be automatically taken care of.
9) Chromatic Aberration
When it comes to lateral chromatic aberration,the Zeiss 35mm f/2 does show quite a bit of it, averaging over 1.5 pixels at wider apertures, as shown below:
Longitudinal chromatic aberration (which is the effect of color fringing in front of and behind the focused area) is certainly visible when shooting at large apertures:
See how the color on the front of the chart (where the number 6 is) is purple, while on the back of the chart it is green? That’s the effect of longitudinal chromatic aberration. Most prime lenses including the Nikon 35mm f/1.4G have a similar problem though, so no surprises here.