Contax 645 Lens System

All the Japanese-made Zeiss lenses for the Contax 645 are expensive. They are generally cheaper than Zeiss or Schneider lenses for the 6x6 Rollei and Hasselblad cameras, but cost substantially more than their 645 counterparts of other brands. Obviously the Zeiss name carries a hefty premium. On other hand, the Contax 645 lenses are very well made. In every respect, and they rank among the best constructed lenses I have seen in medium format. They are also among the fastest of any medium format lenses.

In this review I'll concentrate on the three lenses that I have--Distagon 45mm/F2.8, Planar 80mm/F2, and Sonnar 140mm/F2.8.

Construction

The Contax 645 lenses exhibit characteristics of cost-no-compromise optics. Lens elements are precision housed in all-metal barrels. Even filter and lens hood threads are metallic. All the electrical contacts are gold plated for better conductivity and prevention of oxidation, and the aperture ring on each lens have reassuring clicks when turned. Unquestionably, every aspect of the lenses exudes quality of materials and precision craftsmanship. Whether or not this costly construction yields any real world benefit, on the other hand, can be argued from both sides.

Many AF lenses I have used in the past have compromised MF performance. The focusing ring is usually too loose and gives a feeling of imprecision. To the contrary, the Contax 645 lenses do not have this problem. The dampening on each lens is silkily smooth and comparable to the best MF lenses. Also the DOF scales on the Contax lenses are on par with most MF lenses and are vastly better than the majority of AF lenses on which tiny and vague DOF scales are found.

AF Performance

As stated in the review of the Contax 645 body, the AF performance is sufficiently good but far from state of the art if compared to top 35mm SLRs.

For 95% of photography, I can't see how the AF performance will be a limiting factor. For me the AF only becomes slow when trying to focus from the closest distance to infinity or vice-versa, which is rarely the case in practice. Also, because of the unique AF-MF integration of the system, one can always combine AF and MF to achieve greater speed or precision of focusing depending on the situation.

MTF Charts

The Contax 645 lenses being Zeiss, they inevitably invite comparisons between themselves and Hasselblad counterparts. The most popular comparisons have been made with MTF charts. These comparisons, although potentially useful, can also be very misleading.

Zeiss has published MTF charts of all their lenses, including lenses for both the Contax 645 and the Hasselblad systems, at wide open and two stops down. For any given lens, the image quality at wide open is necessarily worse than if the lens is stopped down. So comparing a faster lens to a slower lens using MTF charts invariably puts the faster lens in disadvantage. In this case, the Contax lenses are generally faster, and hence at wide open or two stops down, it's reasonable that the Contax lenses would perform less favorably. This explains why, on first look, some Contax lenses have inferior MTF charts. However, this says little about how the lenses would compare if the MTF charts were graphed at the same apertures.

On the other hand, there ARE some MTF charts made at same apertures and are hence comparable. The conclusion coming from comparing these MTF charts is that:

1. Near the center, it's difficult to establish the claim that which lens line is superior. Both lines have superior and inferior performers.
2. Very often the Contax lenses have slightly better corner performance. But this is more than expected since the Hasselblad lenses have a slightly larger image circle, and as a result image quality deteriorates faster towards the corner.

My only suggestion is that one shouldn't rely too heavily on MTF comparisons because given the apertures are different, the MTF charts can't be compared directly. Even in cases where the apertures are the same and MTF charts are comparable, there is no decisive conclusion. Additionally, MTF charts are oftentimes not perfectly indicative of real world performance.

My Subjective Comments on Image Quality

I have tried to compare the Contax 645 lenses to equivalent Hasselblad lenses (CFE/CFi). Generally, I have come to the following conclusion:

1. In practice all these lenses are superb. Excellent contrast and resolution aside, these lenses have amazing shadow details and saturation. The form and texture of objects in particular are presented with surprising accuracy and realism.
2. There isn't a consistently superior line.
3. From a lens to lens perspective, I found the standard lens of the two lines to be approximately the same in image quality. The Contax 80mm Planar is slightly better in corner resolution than the 80mm CFE, but it was never noticeable without a loupe. In the telephoto class, the 140mm Contax is slightly less sharp than the 150mm CFi near the center, but again the difference is only visible under a loupe. For the wide angles, the 45mm Contax has no light falloff throughout the aperture range, where as the 40mm CFE has slight light falloff at the corners at wide open. The falloff disappears if the lens is stopped down.
4. The combination of longer focal lengths and wide apertures makes the 80mm and 140mm lenses for the Contax superb portrait and close-up lenses. They throw the background into a smooth and creamy blur with disc-like highlights and are matched only by the best lenses I've seen. However, it is important for one to note that the shallow depth of field can easily work the opposite way by, for example, having one eye of the subject in focus and the other eye blurry.

All in all, any of the lenses mentioned above delivers excellent image quality. For anyone trying to decide between the two systems, the emphasis should be placed on the inherent functionality differences of the systems. The differences in image quality, in my opinion, are minor and in most cases irrelevant.

Reliability

Having not had any problems using neither the lenses nor the body, there is little I can say about the reliability of the Contax system. However, I'd suspect the Contax 645 system to be very dependable in the long run. First, the Contax uses all-electronic linkages and hence require less maintenance. Second, the system seems to be made to very precise manufacturing standards. Kyocera (the maker of Contax camera bodies and one of Industry Week's World's 100 Best Managed Companies) has shown itself to be a world class leading conglomerate in electronics/materials engineering and manufacturing. I have yet to have any reliability problems with any of my various Contax products. It has also been noted by Contax's Blake Ziegler that the newer equipment used at Zeiss' Japanese production site typically results in tighter quality deviation. (But then again I never had problems with Hasselblad lenses/bodies either, except for regular wear-and-tear and maintenance.)

Lens Wishlist

I'm very pleased with the results I get from the Contax system. Optics-wise, the lenses offer impeccable build quality, reasonable AF performance, excellent image quality, and fast maximum apertures. However, it is obvious that, in order to take the system to the next step, it should be a top priority of Contax/Kyocera and Zeiss to introduce more lenses to supplement the current six-lens lineup. Particularly, the two companies should focus on introducing

1. Leaf-shutter lenses. Although the current focal-plane shutter system provides better results for my photographic style (i.e. 1/4000s top speed), there exists many other users who wish to have the faster flash sync speeds of leaf-shutter lenses.
2. Longer telephotos. The current line up is limited to lenses with focal lengths no longer than 210mm. Longer telephotos will make perfect use of the Contax's AF capability and mobility for wildlife, sports, and portrait photography. In particular, the telephoto lenses I want to see the most are the 250mm and 350mm Superachromats. These lenses are arguably the best lenses ever made and deliver image performance currently far outdistances everything else. I already know of several photographers waiting to switch to the Contax on the introduction of these lenses. (For the time being they are only available for the Hasselblad system.)

More

• Chris Lee's review of the Contax 645 camera itself