After I purchased a sony a7, I have had trouble finding a telephoto lens. I wanted something light, relatively small, with great color, contrast, and bokeh. For telephotos, I prefer 135mm. My first telephoto for the the sony system was a contax 100mm f2.8 makro-planar. I found this lens exceptional, but too heavy and not long enough. I then tried 135mm STF, but again the lens was too heavy and frankly too expensive for the amount I shot 135mm.
For my next lens, I wanted something smaller, lighter, and cheaper with a zeiss rendering. I initially looked at the contax 135mm f2.8 which is supposed to be excellent. Instead, I went with the CZJ 135mm for its lighter weight and the 49mm filter size that matches my 55mm Zony. There are 5 versions of this lens. The lens can have a single coating or several different iterations of a multicoating. I have the last version of the carl zeiss jena 135mm given the test version of the T* coating. Below is a website with more information on the different lens subtypes.
When I look at a lens, the color and contrast matter more than the sharpness. It has to be able to render great color or the sharpness does not matter to me. In shooting this lens,I found that wide open there is great contrast, sharpness, and bokeh. When the lens is stopped down, the lens retains its excellent bokeh. I also really like the color this lens generates. These shots are SOOC for the most part except some highlight recovery. The top image is at f3.5 and the bottom is f5.6.
by [url=https://www.flickr.com/photos/131312380@N06/]Nathan Westcott[/url], on Flickr
Below is another example of the wonderful color and contrast SOOC. This one is shot at f5.6.