Hasselblad Tessar CB 4.8/160 vs. Sonnar CFE 4/180—the ultimate shootout
It is common wisdom among photographers using Hasselblad lenses that the Sonnar CFE 4/180 is one of the most outstanding and "legendary" performers; at the same time, the Tessar CB 4.8/160—or, indeed, the entire "CB" line—quite often gets beaten like a red–headed stepchild. As one normally would not want to keep two lenses of very close focal lengths a preference towards the Sonnar seems quite obvious at first. A closer look, however, uncovers that they actually have several significant differences—while the Sonnar is said to be a noticeably better optical performer the Tessar is smaller, lighter and considerably cheaper. This poses an intriguing question of whether the Sonar's better optical performance suffices to justify the difference in price and give up the Tessar's lighter weight and smaller size. Although this question is unlikely to have a simple answer, a detailed look at the differences between the two lenses should provide a good basis for making an intelligent choice—hence the shootout.
Below the two lenses are compared with respect to the following aspects: handling, light fall–off (also known as vignetting or unevenness of illumination), sharpness, distortion and bokeh. All tests were done using Fuji Velvia 100F slide film, a sturdy tripod (Gitzo 1227) with a solid ball–head (Kirk BH–1), MLU (mirror–lock–up), a cable release, a lens hood and no filters. Test slides were then examined on a light table using 10X and 15X loupes.
It has been mentioned elsewhere that the CFE 4/180 does not balance perfectly on a Hasselblad 503cw camera body and that the CB 4.8/160 is a better option for extended periods of hand-held shooting. I generally tend to agree with this—the Sonnar is a bit on the long side and, quite peculiarly, front–heavy (especially when focused at close distances), which slightly strains your left hand when you hold a camera with the lens attached to it. To deal with this issue I have developed the following hand–holing technique: while upholding the camera with my left hand I support the lens with the index finger of my right hand so that the camera/lens combination feels stable in my hands; I then use my right hand's thumb and middle finger to focus the lens. Although this method helps I would choose the Tessar if I had to pick only one lens on the basis of suitability for hand–held work and without consideration of the other factors.
Wide–open: I know that these are different aperture settings (f/4.8 vs. f/4) but this is the most relevant real–life comparison—when using large apertures chances are you do not want to particularly use f/4.8 or f/4 but simply need/want to shoot wide–open. Here, the Tessar appears to exhibit a somewhat lesser amount of light fall–off yet, as it is less gradual, the aberration is more apparent in slides. I would give the edge to the Sonnar.
f/5.6: The Sonnar's light fall–off is noticeably less evident and more gradual—for practical purposes I would consider it non–existent at this aperture. In case of the Tessar unevenness of illumination might still be visible in the corners in certain types of photographs.
f/8: the Tessar still shows a slight presence of the aberration in the furthest corners.
All in all, the Sonnar has a better light fall–off signature—it is more gradual and disappears faster as you stop the lens down. This being said, though, both lenses perform sufficiently well for the majority of real–world applications.
To cut a long story short, in absolute terms the Sonnar is marginally sharper at 10X magnification and, as expected, at 15X magnification the difference in sharpness is more evident. I, however, have to emphasize that given the lenses' reputation I expected the disparity to be much more pronounced—whereas the Sonnar is an excellent performer the Tessar is not a slouch of a lens either. The question, however, remains whether this difference in sharpness is important for your photography and worth the extra money. The answer is quite simple: it depends on how large you normally print. If you seldom produce large prints (20–inch and larger) then the Tessar should fully suffice for your work. If you often print huge photographs (again, 20–inch and larger) where small detail is important (e.g., landscapes; this, obviously, would not be important for portraiture) then the Sonnar is a better option.
Both lenses exhibit a very slight pincushion distortion of comparable magnitude that would require very specific subjects and compositions for it to be noticeable. I would call it a draw.
I specifically composed the picture above so that there are large out–of–focus areas in it. The crops below are the area of the image marked in red.
Tessar CB 4.8/160 bokeh @ f/4.8
Sonnar CFE 4/180 bokeh @ f/4
Tessar CB 4.8/160 bokeh @ f/5.6
Sonnar CFE 4/180 bokeh @ f/5.6
Tessar CB 4.8/160 bokeh @ f/8
Sonnar CFE 4/180 @ f/8
What I see in the above crops is as follows: the Sonnar has a noticeably better bokeh wide-open (this actually is consistent with my overall experience with the two lenses—I in fact have never been entirely happy with the Tessar's performance in terms of bokeh at this aperture) and a marginally better bokeh at f/5.6; I tend to think that the difference in how out–of–focus areas are rendered at f/8 is insignificant (if there is any difference at all, that is). On the whole, the Sonnar has the edge.
As expected, optically the Sonnar CFE 4/180 is a better lens, which basically is manifested in an overall better performance at large apertures (f/4—f/5.6) and a marginally better sharpness throughout the whole range of aperture settings. Once again, though, the Tessar CB 4.8/160 is a fully competent lens that produces image quality fully consistent with what one would expect from Carl Zeiss and I was really surprised at how well it held its own against the neighboring legend.
Having analyzed the factors above choosing between the two lenses should not be difficult now. If one needs fine detail in large enlargements and/or the ultimate sharpness in this focal length range then the Sonnar is the best option. For those who frequently shoot wide–open, which quite often also means hand–holding the camera, the choice is slightly more difficult as one has to choose between better hand–holdability (the Tessar) and nicer bokeh and more gradual light fall–off (the Sonnar). Otherwise, the Tessar CB 4/160 is a great performer and represents a better value for the money.
Considering the fact that the CFE/CFi lenses overall are at least marginally better than their predecessors (CF, etc. lenses) as well as all the improvements common to the CB and CFE/CFi lenses (better ergonomics, enhanced stray–light handling and smoother focusing), I personally would choose the Tessar over the neighboring CF or earlier lenses.
The tests were done with film only and I imagine that high megapixel digital backs would magnify the difference in sharpness between the two lenses. At the same time, the crop factor of the current digital backs (or, indeed, the advantages of digital post-processing) is likely to eliminate the difference in light fall–off signatures. Likewise, distortion would be even less noticeable.
Related article: Hasselblad Sonnar CFi 4/150 vs. Sonnar CFE 4/180—making the choice