Carl Zeiss Distagon T* 28mm f/2.8 ZF

 

Introduction

Carl Zeiss Distagon T* 28mm f/2, announced in Fall of 2007, is one of the latest additions to the growing lineup of SLR lenses that Zeiss introduced after discontinuing its Contax brand name. The 28mm joins two other wide angles, Distagon T* 25mm f/2 and Distagon T* 35mm f/2, both of which were introduced back in 2006. Many believe that the new 28mm variant is the 'reincarnation' of the almost legendary 'Hollywood' Distagon T 28mm f/2 that Carl Zeiss used to manufacture for Contax/Yashica mount. I can't really confirm (or deny) that, but comparing the optical layout of both variants reveals that they look quite similar with one exception - the new design introduces an extra element in the middle lens group, which, one would hope, improves the optical characteristics of the lens. Zeiss currently manufactures Distagon T* 28mm f/2 in Nikon Ai-S (ZF) and Pentax K (ZK) mounts. The lens is priced at ~US$1,000 at online retailers like B&H.

The optical construction of the lens consists of 10 elements in 8 groups. Build quality of the lens is superb, and like with all other SLR lenses in its current lineup, Zeiss chose a durable, all-metal barrel with metal aperture and focus rings. Focus ring is smooth and aperture ring snaps very nicely, moving in 1/2 f-stop increments. The minimum aperture is f/22. Like all manual lenses, Zeiss 28mm f/2 ZF has a depth of field scale engraved on the barrel. The lens looks and feels quite sturdy - a  feast to my eyes, especially after all these plastic, flimsy looking modern lenses. The lens weights 530g (1.16lb) - certainly not the lightest wide angle on the market, and measures 65 x 94mm (2.5 x 3.7in). The inner cam of the lens extends slightly during focusing towards closeup, adding a few millimeters to the total length. The lens accepts 58mm screw-in type filters and has the minimum focusing distance of 24cm (0.78ft).

Image

The factory box includes Carl Zeiss Distagon T* 28mm f/2 lens, front and rear caps, metal lens hood, quality control card and manual. The lens tested in this review was manufactured to fit Nikon's Ai-S mount. When using the lens on Canon EOS bodies, I relied on generic Fotodiox Nikon F to EOS adapter without AF confirmation. On an APS-C body with 1.6x crop factor, the lens has field of view similar to that of a 44mm prime on a full frame camera, thus loosing its wide angle appeal.

 

Summary
Lens Composition 10 elements in 8 groups
Angular Field 74 degrees
Minimum Focus 24cm/0.78ft
Focusing Action MF
f-stop Scale f/2-f/22, manual
Filter Size 58mm
Lens Hood Metal (included)
Weight 530g/1.16lb
Dimensions 65x94mm/2.5x3.7"
Lens Case N/A

 

Field Tests

The lens produced exceptionally good results in the field, with images remaining tack sharp across the frame and throughout the aperture range. There was no major visible degradation in quality around borders even at the widest aperture setting. Color reproduction was exceptionally accurate and images carried excellent contrast, again throughout the aperture range.

 

ISO 400, 1/200, f/2, 28mm (FF)
ISO 400, 1/200, f/2, 28mm (FF)

 

The lens shows rather mediocre handling of bokeh. OOF highlights are pretty round and mostly uniform, but have bright, well defined edges, which hints on the over-corrected spherical aberration. Near and far object OOF contrast transitions remain somewhat sharp and there's a minor hint of double-edging in the background objects.

 

Vignetting @ f/2 - full frame vs 1.6x crop
Vignetting @ f/2 - full frame vs 1.6x crop

 

The lens showed moderate level of vignetting on a full frame body at f/2. Stopping down to f/2.8 reduces vignetting to pretty minimal levels and by f/4 vignetting is all but gone. On an APS-C camera, the lens takes advantage of the smaller sized sensor and showcases pretty much no vignetting throughout the aperture range. Distagon T* 28mm f/2 ZF shows minor color fringing, mostly around borders pretty much throughout the aperture range (you can see thin pink strips in the window and balcony shadows on the left side of the street picture found in the image samples section). Both barrel distortion and flare were well under control.

 

ISO 100, 1/1600, f/2, 28mm (100% crop)
ISO 100, 1/1600, f/2, 28mm (100% crop)

 

Lab Tests

Please note that MTF50 results for APS-C and Full-Frame cameras as well as cameras from different manufacturers are not cross-comparable despite the same normalized [0:1] range used to report results for all types of cameras.

 

Nikon FF: Coming soon...

 

Canon APS-C: The lens showed outstanding characteristics in the lab. On an APS-C camera, Distagon T* 28mm f/2 ZF demonstrated exceptional performance in the center, with images remaining tack sharp from f/2 all the way through f/11. While performance at f/2 is already outstanding, once stopped down to f/5.6-f/8 it becomes simply breathtaking. Border performance is as exceptional pretty much throughout the aperture range. At f/2 image sharpness is pretty decent but somewhat lags center performance, but once stopped down to f/2.8 quality shoots up and remains on very high level throughout the rest of the aperture settings. Performance peaks around f/4-f/8 where the lens also achieves the most balanced results across the picture frame. At its peak, the lens is capable of producing outstanding 19in prints, which puts it into the top quartile of wide angle lenses I tested so far. Conclusion? So far, so good... I've been holding pretty high expectations for this lens and it certainly does not disappoint when it comes down to performing on an APS-C body. Overall image quality is consistently high and is comparable with the best of the best in the industry.

 

MTF50 (Line Width/Inch on the Print) @ 28mm
MTF50 (Line Width/Inch on the Print) @ 28mm

 

Normalized raw MTF50 @ 28mm
Normalized raw MTF50 @ 28mm

Chromatic aberration on an APS-C camera was mostly under control. CA in the center was quite low, generally not exceeding ~0.5px at f/2 and dropping to ~0.4px by f/4, staying at this level throughout the rest of the aperture range. CA around borders was somewhat higher, approaching ~0.9px at f/2. CA is reduced slightly with stopped down aperture, and from f/4 through f/11 it stays at ~0.6px.

 

Chromatic Aberration (APS-C) @ 28mm
Chromatic Aberration (APS-C) @ 28mm

 

Here are 100% crops, taken with an APS-C type Canon Digital Rebel XTi, comparing image borders at f/2 and f/8.

Image borders @ 28mm (100% crop): f/2 vs f/8
Image borders @ 28mm (100% crop): f/2 vs f/8

 

Canon FF: Distagon T* 28mm f/2 ZF shows quite impressive performance on a full frame Canon 5D. Image sharpness in the center is as good as it can ever get (at any aperture setting) - here Distagon rivals pretty much any lens out there. Border performance is lagging a bit at f/2 - here quality is good, but not exceptional. This changes once stopped down to f/2.8 and border performance from f/2.8 through f/11 is top notch. Performance peaks around f/8 and here the lens also achieves the most balanced results across the frame. Conclusion? We have a winner. Sharpness-wise, Distagon T* 28mm f/2 is the king of the jungle (so far at least) and showcases performance that should not disappoint even the most demanding user.

 

Normalized raw MTF50 @ 28mm
Normalized raw MTF50 @ 28mm

 

Chromatic aberration on a full frame Canon 5D was also more or less under control. Center CA was quite low throughout the aperture range, generally not exceeding ~0.5px. Border CA was higher, especially with wide open aperture where it averaged ~0.9px. Not a disaster but you might have to fix occasional artifact in your favorite imaging software. CA drops with stopped down aperture and Distagon 28mm f/2 ZF is no exception here. By f/4 ZA drops to a manageable ~0.6px and remains at this level throughout the rest of the aperture settings.

 

Chromatic Aberration (FF) @ 28mm
Chromatic Aberration (APS-C) @ 28mm

 

Here are 100% crops, taken with a full frame Canon 5D, comparing image borders at f/2 and f/8.

 

Image borders @ 28mm (100% crop): f/2 vs f/8
Image borders @ 28mm (100% crop): f/2 vs f/8

 

Alternatives

Assuming you are interested in Nikon mount lenses, the absolutely must have (or at least evaluate) is Nikon AF Nikkor 28mm f/1.4D ASPH. Of course this assumes that you can find and afford one. Nikon discontinued this lens back in early 2000s and as of early 2008, this lens has become quite rare, easily fetching over US$2,000 on eBay. For a good alternative glass, it might be worth testing Leica's Elmarit-R 28mm f/2.8 (many users claim that the latest E55 variant is an optical marvel). For something cheaper, but still high quality, take a look at the older and slightly slower Contax version of the 28mm Distagon - Distagon T* 28mm f/2.8 (review). The lens is pretty light and compact, sporting very good build quality and superb image quality. Naturally, Contax 'Hollywood' Distagon T* 28mm f/2 is also worth evaluating (this is also a Contax mount lens), although this lens is not as common as its slower brethren. These two/three decade old lenses perform surprisingly well by modern standards and can give the newly released Distagon T* 28mm f/2 ZF a run for the money. Here is a side by side comparison of the older Contax Carl Zeiss Distagon T* 28mm f/2 and the new Distagon T* 28mm f/2 ZF.

 

Normalized MTF50 (Center): Carl Zeiss Distagon T* 28mm f/2 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF
Normalized MTF50 (Center): Carl Zeiss Distagon T* 28mm f/2 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF

 

Normalized MTF50 (Borders): Carl Zeiss Distagon T* 28mm f/2 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF
Normalized MTF50 (Borders): Carl Zeiss Distagon T* 28mm f/2 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF

You can notice that the new design cleanly outperforms the old 'Hollywood' one around borders but the results are rather mixed in the center, with 'Hollywood' showing slightly better center resolution from f/4 through f/11. And here is a side-by-side performance chart of Contax Distagon T* 28mm f/2.8 and Distagon T* 28mm f/2 ZF (with all side by side comparisons were done with the same full frame Canon 5D camera (identical settings, equipment, lightning etc.).

 

Normalized MTF50 (Center): Carl Zeiss Distagon T* 28mm f/2.8 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF
Normalized MTF50 (Center): Carl Zeiss Distagon T* 28mm f/2.8 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF

 

Normalized MTF50 (Borders): Carl Zeiss Distagon T* 28mm f/2.8 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF
Normalized MTF50 (Borders): Carl Zeiss Distagon T* 28mm f/2.8 C/Y vs Carl Zeiss Distagon T* 28mm f/2 ZF

As can be seen from the charts, both lenses perform more or lens on par, with the Contax variant of Distagon again showing somewhat better performance from f/4 and the ZF variant excelling around borders at wide apertures. All in all, both lenses showcase outstanding performance, but the price difference obviously might influence some users to opt for the slower, older C/Y version of this great lens.

 

Recommendation

Carl Zeiss Distagon T* 28mm f/2 ZF is an exceptional lens. Image quality, build quality, artifacts control - all make this lens a must for serious photographers. On the not so positive side, at almost US$1,000, this lens is certainly not a bargain. Of course one should also keep in mind that this is a fully manual lens, so if you're not used to or don't like the idea of focusing manually, this lens is probably not for you. Also, unless you use Nikon or Pentax cameras, you will have to go through the hassle of finding the right adapter to adopt the lens to your favorite body. But if you bite the bullet and get this lens, it is unlikely that you will be disappointed. Well, at least not until Carl Zeiss decides to release the new version of its legendary Distagon T* 21mm, at which point you will probably have to scrap for funds again.