DSLR users know that “good glass” is necessary no matter the sensor size, and that’s where mirrorless cameras suffer most, with limited lens selection that is often of marginal build quality and too often modest optical performance. Yet demands on optical quality tend to be higher for smaller sensor cameras due to the greater photosite density, at least for similar levels of high quality detail in the same number of megapixels (e.g. 24 megapixels from full-frame vs the smaller APS-C).
Enter the Zeiss Touit lens line for Sony NEX and Fuji- film X. The optics in the Touit lenses are optimized for the APS-C sensor size and for digital without optical design compromises for a DSLR mirror or rangefinder flange focal distance. Also, Zeiss has licensed the necessary electronic protocols from both Sony and Fujifilm for both autofocus and native camera control of the lens.
Overview of the Touit Lenses
Three lenses are available (12/2.8, 32/1.8, 50/2.8), with the 12mm and 32mm, shipped in June 2013, and a 50mm to follow in late 2013.
The Touit lenses offer a high-grade build quality, indeed an elegant feel compared to the majority of mass-produced lenses. Lens hoods are included with each lens and fit seamlessly; the 32/1.8 includes a round hood and the 12/2.8 includes a scalloped hood. Both increase the apparent lens size substantially, but add little weight. When mounted, they fit so well that they appear like a seamless extension of the lens itself. Filter threads are built-in for standard filters so that a filter or polarizer can be easily mounted (12/2.8 = 67mm, 32/1.8 = 52mm).
On Sony NEX, aperture control is through the camera body, but on Fujifilm X, the Touit lenses include an aperture ring. The lens diaphragm itself is an almost circular one with nine blades.
Zeiss opted for metal with key parts, but plastic and rubber for others: the lens barrel structure is metal for reasons of durability, mechanical stability and in order to be impervious to environmental influences. The rubberized and plastic exterior over the barrel is not unlike the announced ultra high grade 55mm f/1.4 Distagon for DSLRs. I like the non-metal lens “skin.”
The autofocus motors make only minor noise. The motors chosen for the Touit lenses are more powerful for longer life and more reliable focusing, in part because of the lens elements being moved internally.
In my studio and field tests with the 24-megapixel Sony NEX-7, Touit optical performance generally matches or exceeds what you might obtain with a Zeiss DSLR lens mounted via adapter, while at the same time offering autofocus and a much smaller and lighter form factor. As with all high-perform- ance lenses, critical focus accuracy is essential for optimal results.
In this regard I was less than satisfied with the Sony NEX-7 autofocus accuracy, and would recommend using the EVF in magnified Live View with manual focus for work where precise focus position matters. Also, the Sony NEX-7 stops the lens down to the shooting aperture even while focusing, which can cause focus ambiguity with any lens: open the aperture for critical focusing, then stop down to shoot.
Both Touit lenses appear to be free of focus shift, which is rarely the case for f/1.4 and f/1.8 50mm lenses for DSLRs. This is a very practical feature that eliminates one hurdle to achieving peak quality.
Zeiss Touit 12mm f/2.8 Distagon
Weight: 264/283/307 grams for lens/+hood/+hood+lens caps (Sony E-mount)
The 12mm f/2.8 Distagon is an ultra wide-angle lens utilizing a high-grade optical design of 11 elements in eight groups with a 99° field angle equivalent to 18mm on full-frame cameras. Field shooting confirms that it has been highly optimized for the APS-C digital format, with extreme sharpness to the frame edges and only a modest sharpness falloff to the extreme corners−exceptional for an ultra wide-angle lens.
Outside, extreme contrast situations fail to provoke any color fringing, even to the edges and corners. Along with exceptional contrast and outstanding flare control (shooting into the sun is fine), the 12/2.8 Distagon delivers images with clarity and color saturation sure to thrill the wide-angle enthusiast. Compared to the 18mm f/3.5 Zeiss ZF.2 / ZE for full-frame DSLRs, the 12/2.8 Distagon outperforms in multiple ways including flatness of field, color correction and control of astigmatism, and it’s 2/3 stop faster to boot!
The Touit 12/2.8 Distagon offers performance even wide open that remains consistent across the frame; images show an appealing uniformity of background blur from center to corners. Bokeh wide open is unusually good if not perfect for strongly out of focus areas, but by f/4 it is very pleasing. Combined with its other optical qualities, the 12/2.8 Distagon is a lens that will surely be appreciated by its user more and more with time. It offers well-mannered performance, a rare find in a fast ultra wide-angle lens.
Distortion is moderate and can be corrected if desired, while vignetting is often more of a useful creative tool than something worth correcting. For field images (raw format on Sony NEX-7), I felt absolutely no need to correct for either (the examples are from Sony NEX-7 raw format and have not been corrected in any way). Also, you cannot help but be impressed with what the Sony NEX-7 sensor can deliver with a high quality lens. It’s clear that optimization for digital is not just a talkingpoint.
In shooting the Touit 12mm f/2.8 Distagon, the outstanding optical correction quickly manifested it- self: sharpness is high, color saturation is rich and there is no color fringing to be found even under demanding lighting conditions. The high lens contrast and color correction lend themselves to outstanding quality black and white conversions from color originals. This is a very high performance lens.
Touit 32mm 2/1.8 Planar
Weight: 203/228/247 grams for lens/+ hood/+hood+lens caps(Sony Emount)
The Touit 32mm f/1.8 Planar is a “normal” lens equiv- alent to a 48mm on full-frame cameras (48° field angle). Field shooting confirms high sharpness wide open, but with modest contrast. The contrast wide open was found to be much superior to several alternatives, so this must not be misconstrued! Stopping down to f/2.8 delivers very high micro contrast, with peak performance reached at f/4.
Across the focusing range the Touit 32mm f/1.8 of- fers high performance near-macro range, head-and- shoulders, or full-length portrait, distance shooting.
As with the 12/2.8 Distagon, the 32/1.8 Planar offers exceptional flare control. In field torture testing it minimized flare even with the sun placed just inside or outside the edge or corner (certain DSLR lenses exhibit extreme flare in those circumstances).
Color saturation is very high in field images. No special glass types are used in the 32/1.8 Planar and so a faint color fringing can sometimes be seen off-center on high-contrast edges. Out of focus, there is secondary longitudinal chromatic aberration (magenta/green blurs) as found in virtually all lenses, but these effects are unusually free of any harsh edge effects and are effectively banished by f/4. Again, context matters: the Touit 32/1.8 appears to be as well corrected (or better) than high quality 50mm designs for full-frame.
One hallmark of the Planar design is pleasing image blur (bokeh), and indeed the most compelling feature of the 32/1.8 Planar is its exceptional combination of bokeh along with high micro contrast for in-focus fine detail. The uniformly pleasing bokeh in front of and behind the plane of focus and even into the extreme corners lends a certain stability and relaxation to the image that steadily seeps into the photographer’s sense of its rendering style. It is “classic Zeiss” and anyone looking for something special will find it here.
Subjects with bright out of focus specular highlights such as glassware are handled beautifully. I had noticed this quality immediately, and each field image I made added to this initial impression, until ultimately I came to see it as a distinguishing characteristic.
As with every 50mm lens for DSLRs, the Touit 32/1.8 has some field curvature but it is at a lower level than most 50mm f/1.4 or f/1.8 designs for full-frame DSLRs while also avoiding focus shift, so this behavior must be understood in context as not perfect, but unusually well behaved. The field curvature manifests mildly as follows: when shooting a “flat” subject (e.g., landscape scene at infinity), stop down to f/5.6; otherwise some areas will drop in sharpness relative to others (which areas are sharpest or least sharp depends entirely on very small changes in lens focus). Again, this behavior is commonplace and not at all unique to the Touit 32/1.8, but should be understood for critical work. Every optical design makes tradeoffs; the author’s preference would be an f/2.8 design with near perfect imaging quality along with an f/1.0 design for high- speed applications.
Distortion of 2.5% could be of concern for some subjects, but in practice I saw little need to correct it (example images are from Sony NEX-7 raw format, and have not been corrected in any way). Vignetting was of no concern whatsoever, and I generally consider it a desirable effect when shooting at wider apertures anyway.
The mirrorless camera market has come of age: an entirely new lens line from Zeiss is an endorsement of the format popularity and future potential of the mirrorless APS-C camera market. High-quality optics might be a tipping point that persuades more pro- fessional photographers to consider a smaller camera system (non DSLR) for some jobs, especially as the sensors further improve.
Shooting the Sony NEX-7 with the Touit lenses in New York City, one thing stood out for me: walk-around shooting is just easier and more fun with a compact system camera than a bulky DSLR: small and light- weight, high quality results, any shooting angle, and perhaps most important, innocuous: no one pays attention to a “tourist” camera, even if it happens to have a high performance Zeiss Touit lens on it.
Editor’s Note: The Touit lenses are reviewed in detail at diglloyd.com