Review Zeiss Batis 25 mm f/2
The Zeiss Batis 25 mm f/2 has both a diameter and a length of about 8 cm, weighs a bit more than 3 ounces, offers a big diagonal field of view of 82 degrees and links that with high brightness. That makes the Batis 25 mm f/2 a dream partner for any camera from the Sony A7 series. The cameras from the Sony A7 series are smaller and lighter than SLR cameras with a full-frame sensor. In that case, it’s also best to choose a lens that fits with that in terms of size and image quality. The Sony FE 24-70 mm f/2.8 G Master offers a bit bitter field of view and, on a Sony A7R II, delivers sublime image quality. But then you do have to accept the extra weight of this impressive lens (886 grams). The Sony FE24-70 mm f/4 is more compact and is lighter, but less bright, and it does not get everything possible out of the Sony A7 sensors when it comes to sharpness in the corners. Maybe a Zeiss Batis 25 mm f/2 will manage it? The Sony A7S II (video and low-light photography) and the Sony A7R II (megapixel monster for studio, landscape or street photography) in particular form unique combinations with the Zeiss Batis 25 mm f/2. The good image stabilization in these cameras ensures that even in low light and with long shutter times, you still get razor-sharp pictures with the Zeiss Batis 25 mm f/2. We tested the Batis 25 mm f/2 with the Sony A7S II and the Sony A7R II.
Zeiss Batis 25 mm f/2: perfect match for Sony A7
|Zeiss Batis & Sony A7R II @ f/2, 1/15 sec (hand-held), 2500 ISO (edited RAW)|
Build and auto focus
The lens design contains 5 lens elements made of special glass types and 4 double-sided aspherical lens elements. The Distagon design, which consists of 10 lenses in 8 groups, is a remarkable choice for a mirrorless system camera. The Distagon design from Zeiss has, to quote the Zeiss website, “a long back focal distance” (loosely translated: “nodal point” or “entrance pupil”). This retro-focus design was invented for SLR cameras in which, in order to make space for the mirror unit, a long back focus distance is necessary. By applying the Distagon design here as well, the length of the Zeiss Batis 25 f/2, despite the shorter focal length of 2 cm, is longer than the Sony FE 28 mm f/2. This 25 mm Zeiss wide angle is even nearly as long as the Sony Zeiss FE 55 mm f/1.8 standard lens, for which the focal length is more than twice as long.
|I suspect that Zeiss, which has designed the Batis series especially for mirrorless Sony A7 system cameras, chose the Distagon design despite the lack of a mirror mechanism in the camera in order to be able to achieve high optical performance in the corners. The Sony A7 sensors are namely equipped with a protective filter of 2 mm thick ("sensor stack"). At first glance, that might seem strange, but you always have to take a thin layer of glass in the region of the sensor into account in the lens design. For users of a large, bright telephoto lens, this is probably not big surprise. Similar telephoto units have a filter slot, into which you have to insert a glass plate if you are not using a filter. If you do not do that, then the optical performance decreases. The sensor stack on the Sony A7 is probably the reason why the performance of wide-angle lenses that you use via an adaptor on a Sony A7 camera show disappointing sharpness in the corners. A lens with a large entrance pupil, like the Sigma 18-35 mm f/1.8 Art, does well with an adaptor on the Sony A7 series, while lenses with a small entrance pupil (read: lenses designed for use on a camera without a 2 mm sensor stack in front of the sensor, or: compact wide-angle lenses) are disappointing on an A7 camera as far as corner sharpness is concerned. |
On the lens, which is delivered in beautiful box, it says that it is built in Japan. The build quality is outstanding, with a modern, matte black appearance without any fluff. There are no buttons at all on the lens. On LensRentals, there is a photo series that lets you see the inside of the Zeiss Batis. In order to achieve the low weight, it is possible that a plastic lens housing was chosen. I was unable to find that out. And it probably makes little or no different to the build quality whether it is metal or plastic. The lens hood is made of plastic in any case. That’s nice if the lens hood happens to take a blow when you accidentally bump the Batis into something. You can mount the lens hood backwards on the lens for transport. As far as I’m concerned, the markings that help you to place the lens (a small blue point) could have been a bit bigger. If you have to change a lens in the dark by feel, that helps.
Focus and auto focus: a class apart
Manual focusing with the Zeiss Batis is a unique experience. It makes a difference whether you turn the focal ring quickly or slowly. In the first case, you only have to turn the ring a small distance, so that you can work quickly. In the latter case, you have a very long focus arc, so that you can focus accurately. Normally, a lens either has a focal ring with a small focus arc, so that you can focus quickly but with which it is difficult to choose the focus distance very precisely, or a lens has a very long focus arc, so that you can focus very accurately, but with which you cannot work as quickly because of the big focus arc. The rubber focus ring has no texturing, so I can imagine that focusing is more difficult if the lens is wet, or if you are wearing gloves.
Unique premier: lens with an OLED screen for focus distance and focal depth
|When you turn the camera on, the word “Zeiss” briefly appears in a window on the Zeiss Batis 25 mm f/2. After that, the focus distance is shown, together with the focal depth. That you can easily read this information is a dream of many photographers who make use of the hyperfocal distance in order to create the maximum focal depth. You can let this be shown in feet or meters. You determine whether the Batis only shows the information for manual focusing or for both manual and automatic focusing. You can also turn off the display, so that no information is shown. Watch the video above on Zeiss's YouTube channel to see how that works. |
The OLED scale of the Batis is much easier to read than the traditional focal depth scale that you can find on lenses with a mechanical focus ring. And then don’t even think about photographing in the dark, where reading a traditional focal depth scale becomes impossible. It is also more accurate than a traditional focal depth scale, for example because the focal depth depends not only on the lens, but also on the size of the pixels on the sensor. Whether you calculate the focal depth for a 25 mm lens on a Sony A7S II (12-megapixel, full-frame sensor) or for a Sony A7R II (43-megapixel, full-frame sensor) matters. The Zeiss Batis takes that into account: I focused to 20 cm on both cameras. The focal depth indicated in the OLED was different. To summarize in German: Supertoll!
No screen lasts forever, while a lens often lasts for decades. I am curious whether you can replace the screen when the OLED screen dies, or if it appears that the OLED screen has become too dark. And what that will cost. I expect that, if such a thing were to happen, most photographers would just resign themselves to not having focal depth information anymore. That’s what we’re used to from most other lenses anyway.
As with all the wide-angle lenses that we have reviewed on a camera with a full-format sensor, the vignetting at full aperture (1.5 stops) is clearly visible, for example if you photograph an even blue sky. With stopping down 1 stop, the amount of vignetting is halved. It decreases a bit more with stopping down further, but depending on the subject, you can still see it. The test camera was set to correct for vignetting. Even so, the jpg files showed just as much vignetting as the RAW files. If you apply a lens correction profile in Lightroom or Photoshop, then the vignetting is negligibly small at all focus distances. At full aperture, the vignetting in a corrected RAW file was already less than 0.1 stops.
Image stabilization Zeiss Batis 25 mm f/2
The Zeiss Batis 25 mm f/2 has no built-in image stabilization. It doesn’t need it either. The Sony A7 II, A7S II and A7R II all have effective built-in image stabilization. Only owners of the first A7 series cameras cannot make use of image stabilization. The benefit you can get out of image stabilization depends on the focus distance. At very short focus distances, the benefit is less, because the movement of the photographer during a very long shutter time is so great that the sensor can no longer correct for it. At very long focus distances, a very small vibration causes very big shifts in the image, so that again the image stabilization on the sensor cannot correct for it.
Sharp from corner to corner
The jpg files directly from the camera and RAW files converted in Photoshop or Lightroom show strikingly even sharpness from corner to corner. At full aperture, the center sharpness is already high, but at f/4, the highest center sharpness is reached. At f/2, the sharpness in the corners is visibly lower than in the center, but with stopping down 1 stop, that difference is significantly smaller. Over the traditional working range for which most people use a wide angle (f/2.8-f/11), the Zeiss Batis 25 mm f/2 shows very high detail sharpness and high contrast across the whole image. If you mouseover the diagram above, you see the difference in sharpness between jpg and RAW files saved simultaneously in the camera. The corners and the edges benefit a bit more from sharpening than the center does, as can be seen by comparing the MTF50 measurements for jpg files with unsharpened RAW files (converted outside Photoshop or Lightroom). I can imagine that the MTF50 measurements in the corners—certainly at full aperture—are influenced by vignetting. Due to vignetting, the corners are darker and lower in contrast. That difference becomes less when you convert a RAW file with Photoshop or Lightroom and look at the images without sharpening. We also see this with other wide-angle lenses on a camera with a full-frame sensor, and I am planning to investigate why that is.
Zeiss Batis & Sony A7R II @ f/2, 1/15 sec (hand-held), 2000 ISO (edited RAW shot)
Little chromatic aberration, flare or distortion
|The T* anti-reflection coating of Zeiss works very well, so that you have no trouble with flare and ghosts under normal conditions. Certainly not when you use the included lens hood. Only if a very bright light source is shining directly in frame can you encounter ghosts and flare. For night shots in which there is street lighting, flare and ghosts were present, but it is much less disruptively present than with other wide-angle lenses on a camera with a full-frame sensor. |
For testing, we use all possible in-camera lens corrections and we simultaneously store a RAW file that we analyze outside Photoshop or Lightroom without any lens corrections applied. The color shift (LACA: lateral chromatic aberration) is less than 1 pixel in the corners of the uncorrected RAW files, which is good for a wide-angle lens on a camera with a full-frame sensor, and it is well corrected in the jpg files. In Lightroom and Photoshop, the RAW files are also simple to correct for LACA.
Longitudinal chromatic aberration/color bokeh ("LOCA"), which only occurs with bright lenses, is sometimes recognizable from green edges in the background blur or purple edges in the foreground blur. Even so, LOCA, actually only visible at f/2, is limited. You can correct LOCA in Photoshop or Lightroom, but not automatically, like LACA.
The distortion measured with Imatest amounted for both the RAW and the jpg file to 0.45% and a bit more at very short distances. That is an amount that will not bother you in practice. For architectural or reproduction photography, you can correct it if needed.
Bokeh with a wide angle!
|Zeiss Batis & Sony A7R II @ f/2, 1/15 sec (hand-held), 10,000 ISO (crop) |
When reviewing wide-angle lenses, we practically always write that you do not buy this kind of lens for the bokeh. Because of the short focus distance, the focal depth is so large that any bokeh does not come into its own with wide-angle lenses. But with fairly extremely bright wide-angle lenses, like this Batis, it is possible to play with background blur. If you creep up over your subject, the shortest focus distance of the Batis amounts to just 20 cm, then you can play with background blur at f/2. This increases your creative options. The Zeiss Batis has a beautiful bokeh, where cat’s eye bokeh becomes visible in the corners as a result of vignetting. When testing wide-angle lenses on a camera with a full-frame sensor, I have not come across any lens for which that was not the case. The Zeiss Batis does well on this point. Sometimes, an onion ring pattern can be seen in the bokeh, and with our standard test set-up a kind of zipper in the bokeh could be seen. The onion rings are the result of the aspherical lens elements that are used. As far as onion rings are concerned, the Zeiss Batis 25 mm f/2 has to acknowledge its better in the Sony FE 24-70 mm f/2.8 G Master.
|Look in list of reviews per focal length or our list of reviewed lenses to compare this lens with other lenses. |
WYSIWYG score: This table shows the performance of this lens if you save the files in the camera as jpg, where you have applied all available in-camera lens corrections. This score gives you for this lens/test camera combination: "What you see is what you get".