Sony Carl Zeiss 135mm F1.8 ZA Sonnar T* A-mount lens review by artuk
|artuk#2823 date: Oct-6-2007|
flare control: 5
|ownership:||I own this lens|
Good image from full aperture
|negative:||Very high contrast|
Average to Poor bokeh
|comment:||The ZA 135 appears to be an all new design for ZA Sony Minolta mount, and represents the fastest 135mm prime lens ever made for an AF camera system (Canon et al have an f2 design). It is a full frame lens so is backward compatible with Minolta AF film bodies. As a result of its maximum aperture, the front element is a 77mm filter mount (an unusual size compared to Minolta lenses, which typically were made as 72mm). It is a very heavy lens, around 1kg, and it also "fat" for its length, the lens body the same girth from the filter ring until the lens mount. It has a single focus hold button.|
Personally, I find hand holding this lens can be tiring. Shooting in portrait aspect especially, it is diffcult to support the lens and use the focus lock button, though anyone with smaller hands may have difficulty is either orientation. I find the weight on camera, even on a body such as the Dynax 7 (film) is very front heavy, making it difficult to support easily without camera shake in poor light. (Admittedly, its alot harder to run out of light when you can shoot a f1.8!). I would suggest it is important to support the lens when carrying it on camera, as cheaper plastic bodies may be unduly stressed by the weight if only the camera is held. It size and weight sometimes make it hard to handle, and it is not an ideal lens for travelling light!
Build all metal, although the deeply knurled focus ring (as with other Sony designs) seems to be a magnet for dirt and dust, and is hard to clean due to the depth of the knurling. The lens comes with a very deep metal lens hood and a faux leather draw-string pouch, which unfortunately is excessively tight when the lens is stored inside with the lens hood reversed.
I have marked it down for build as my copy has developed the known problem where the section of the lens body in front of the manual focus ring becomes loose. It is known to fail completely in some cases, and when fixed can re-occur.
Sharpness is very good from full aperture. There is some evidence on full frame of vignetting at f1.8, this appears to clear up around f2.8. Performance improves wih stopping down, as expected, improving through f2.8 and f4, and probably reaches its peak around f5.6. The design clearly uses high edge contrast in order to boost sharpness, or perceived sharpness. Other tests of resolution that I have seen clearly show it is a high performance design, but not significantly higher than other quality lenses in this class. I would suggest that the high edge contrast is what makes it's sharpness very apparent - it is certain visible even on 6"x4" prints.
Colour is good and reasonably well saturated, though I feel the colour is less saturated than some Minolta designs. Although Zeiss lenses are often regarded as "neutral", I find it difficult to judge neutrality. Certainly, given that Zeiss designers have always tended to focus on resolution performance, this was often at the expense of neutrality and colour and contrast consistency from design to design. The lenses were often high contrast as a result of their resolution targets. The colour is good, but different from Minolta designed / coated lenses. I would suggest that it lacks the "liquidity" of colour and overall image compared to the best Minolta designs.
The high contrast nature of the design sometimes seems to have some side effects. Highlights seem to "blow out" more easily than other lenses, perhaps 1/3 to 2/3 of a stop earlier. As with some other very high contrast lenses I have used, in very bright or contrasty conditions it sometimes seems to yeild over-bright and somewhat washed out colours and images. It is hard to define exactly what is causing this, and it may be a fault or result of the printing process. In more moderate contrast conditions, overall colour and contrast is very good. In mixed scenes or in poor light, shadow detail does not seem to be held particularly well, and shadows tend to block up early, even on film with its wider lattitude than digital.
The combination of 135mm length, close focusing to 80cm (1:4), and that fast f1.8 aperture can be used to easily create slectivr focus and depth of field effects. Indeed, at larger apertures care must be taken as depth of field can become so narrow it is paper thin. In my opinion, the "bokeh" and nature of the defocused areas of the image are not particularly good. Highlights tend to be particularly bright, and "circles of confusion" (discs of light) appear to be produced not only from true highlights (points of light) but also any lighter areas of the image. Even mid-tones seem to be rendered this way a little, backgrounds being made of many intersecting defocused circles of confusion. In some cases, true highlights render circles of confusion with bright edges and dark centres. The high contrast design seems to be in part responsible. Additionally, backgrounds are often rendered darker than with other lenses, leading to almost black backgrounds where mid-tones stand out as bright details. In general, the ability to handle out of focus shading and tone is not good in my opinion. I can be used to easily create depth of field and out of focus effects, but the nature of those out of focus effects in not especially good in my opinion.
I have seen no evidence of distortions, which you would be as expected in a fixed length tele lens.
I have not experienced any problems with flare, the deep hood protecting the large front element from the problems of stray light hitting it at incident angles. I have not tried shooting into light sources with it, so cannot comment on that aspect of its performance.
Overall, it is difficult to sum up. The fast maximum aperture allows use in lower light and for candid use, and the sharpness is always very good. However, as already noted, highlights tend to burn out easily, shadow details are not held particularly well, and bokeh is mediocre. For me, it lacks the apparent "magic" of pictures taken with the best Minolta lenses, and lacks the liquid colour and tonality of those designs. These are important aspects of overall image quality, and sometimes I find the obvious sharpness at the expense of other image qualities a little "disappointing". It is a very personal view.