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Field Tests

Over the period of about two years since the first publishing of this report, I had the opportunity to compare a total of three different samples of this little lens. I did not have a chance to compare all three side by side, so the field test results described below are general notes with observations applicable to all versions of this lens I tested. There is an occasional commentary about some minor difference here and there, mostly done from memory, but those are few. We should not, however, rule out the difference between the samples simply due to the fact that their service history is simply unknown. It is worth mentioning that as far as I  know, there were no optical changes from an AE version of the lens to the MM version, so some optical characteristics such as resolution should remain the same between 'good' samples of this lens. The three versions of the lens were an AE copy made in West Germany, and two MM copies made in Japan.

The Sonnar T* 85mm f/2.8, like its larger and faster cousin, Planar T* 85mm f/1.4, is your typical all-manual lens, so there is really not that much to report on the lens, functionality-wise. Ergonomics of the lens are typical of any other Contax branded lens of that era - nice smooth movements of the focusing ring, also smooth , slightly damped, aperture ring that requires just a little bit of pressure when switching from one setting to another. Many users actually prefer the mechanics of the old Contax design to the newly released ZF/ZK series, which have an aperture ring that has an even higher resistance d very abrupt, Leica-like, feeling when rotating the aperture ring.

It is commonly believed that Sonnar lenses, including the 85mm version reviewed here, are more often then not inferior to the similar Planar designs. Planars certainly offer faster apertures and therefore also fetch higher premiums. Technically speaking, the biggest difference between the designs is the number of lens groups used, with Sonnars typically having three or four groups, while Planars typically having five or more. The fewer number of lens groups in the Sonnar design means fewer glass surfaces, which in turn typically results in better contrast and lower amount of flare, all while still maintaining a more compact form factor. Sonnars however are not available in shorter focal lengths  - the shortest one for SLR cameras is the 85mm, this is due to the interference with the camera's mirror box (Sonnars are available in shorter focal lengths for rangefinder cameras simply because the rear element of the rangefinder lens can protrude much deeper into the camera since there's really no mirror to interfere with). The bottom line is that Sonnars often actually offer a very even performance across all aperture settings, including with wide open apertures, while other lens designs, including Planars and even more so Tessars, need to be stopped down a couple of apertures before they can deliver quality that your little Sonnar produces even with a wide open aperture. That was certainly the case with three or four different Sonnar lenses I tested so far, including 180mm, 135mm and now obviously 85mm primes. No kidding! All three 85mm Sonnars delivered superb image quality with very little visual variance from sample to sample and from aperture to aperture. The resolution remained consistent and adequate, I'd say, for the majority of users out there.

With pretty uniform image quality throughout the aperture range, let's take a look at some other characteristics of this nifty lens. Considering that the Sonnar T* 85mm is a moderately fast medium telephoto, one can imagine using it for portraiture type of work. So as with other fast and moderately fast lenses, we want to take a look at how the lens draws at its maximum aperture. You might obviously end up using the lens for portraiture work at other apertures as well, but the wide open aperture would give you the most control over background/foreground separation through the combination of a thin DOF and close minimum focusing distance. Again, as I have noted in other reviews, testing all possible combinations you'd get at different focusing distances and aperture levels is beyond the scope of this review, so we will discuss only the case when you shoot with wide open aperture and at close to minimum focusing distance. This setting (usually) produces the thinnest DOF and hence blurres the background most, helping create (hopefully) dreamy bokeh. And that's what we're after with fast lenses.

The two shots below give you a feel for what the DOF will look like in real life when you use the lens at the minimum focusing distance. Notice the white, milkish covering the right bottom side of the image? I was really puzzled by this since after taking a few  pictures with the lens (this was an AE copy by the way) and processing them home, all my f/2.8 shots had this white band. I initially thought that I might have accidentally covered a portion of the front element with my finger, until I realized that this is actually flare! The sun was hitting the lens from above at ~80 degrees, but the flowers were located under an extendable patio roof, and with the sun rays partially blocked by the roof I never bothered checking if I get a lens flare. After realizing that I actually run to the street to re-test the lens for flare, but I will talk about this later.

Ignoring the flare for the moment, you will notice that the lens provides sufficient amount of blurring in the background, rendering both medium and far positioned objects into incoprehensible blurbs of color. However, the white flower, which is positioned closest to the one in focus leaves somewhat busy impression since the flower buds are not blurred sufficiently. Stop down to f/8, and the background starts to carry even more definition, creating a rather distracting to the eye pattern.

 

ISO 200, 1/2500, f/2.8, 85mm (Canon 5D)
ISO 200, 1/200, f/8, 85mm (Canon 5D)

 

Generally speaking, Sonnar T* 85mm f/2.8 seems to do just fine with far distance objects and not so well with 'stuff' that is located close to the object in focus. The shot below, also taken at the minimum focusing distance, demonstrated that - there's decent amount of blurring around the plush toy in the far background but not so much around the nutcracker figurine and the glass. Not enterily surprising - f/2.8 leaves too much DOF to blur them sufficiently. The good news however, is that the OOF areas do not really have harsh edging to them and there is no sign of any double edging around objects.


ISO 400, 1/60, f/2.8, 85mm (Canon 5D)
ISO 400, 1/60, f/2.8, 85mm (Canon 5D)

Ok, so let's now talk about the flare. After running into the rather unexpected flare while testing DOF, I run to the nearby strip mall to stress the lens a little bit more. Flare handling turns out is the only major difference between an AE copy and MM copy of the 85mm Sonnar. The two shots below show how AE version handled some extreme situations, with the sun peeking over the top of the building on the right hand side and hitting the front element of the lens at ~70 degrees. Needless to say, flare handling in AE lens at least is not particularly impressive, with ghosting and glare visible throughout the aperture range. While I don't have similar shots done with an MM lens at the moment, the two copies I've had on my hands over the last two years have not showed such a heavy flare, which leads me to speculate that there might have been some minor changes in coating when Zeiss transitioned from AE to MM version. I will try to re-shoot the same situation with an MM copy in the future and report back in the review.

 

ISO 400, 1/400, f/2.8, 85mm (Canon 5D)
ISO 200, 1/40, f/8, 85mm (Canon 5D)

 

The lens produced very minor vignetting with wide open aperture on a full frame Canon 5D and once stopped down to f/4, vignetting becomes pretty much non-existent. On an APS-C camera with 1.6x crop factor, the lens showed basically no vignetting throughout the aperture range.

 

Vignetting @ f/2.8 - full frame vs 1.6x crop
Vignetting @ f/2.8 - full frame vs 1.6x crop

 

As mentioned earlier, Sonnar designs usually offer good to excellent contrast and color reproduction capabilities pretty much throughout the entire aperture range. Sonnar T* 85mm f/2.8 is another validation point for this, as the lens showcased accurate and neutral color palette straight from f/2.8, with very good amounts of contrast in both mid-tones and shadows. The rendering quality, while not necessarily completely unique, should be quite pleasant, as long as you shoot under normal conditions of course.