Conclusion: Of course it is fine quality, fast focusing, and tack sharp. I knew all that before I bought it. What has continually stood out to me about my 135 is how BEAUTIFUL my photos turn out; so very pleasing to the eye. For my needs (and low light photography is one of the things I really enjoy) IS would not be a meaningful addition to this lens. This lens is a bargain. It is also a specialist.
Conclusion: I had read for years that this was perhaps Canon's sharpest prime. After shooting with it for several months now, I have to agree. The focal length is a little bit of an adjustment when shooting casually on a hike or in the street, especially if you are used to a 50mm or zoom, but once you get comfortable, this lens will hardly leave your camera. With a still subject, such as an arranged portrait, this lens shines.
Summary: Let me start off by making one simple statement: Oh. My. Gosh. That absolutely sums up what I think about this magnificent lens. When I was looking for a replacement to my Sigma 70-200 f/2.8 behemoth of a lens, I was only interested in sharpness. With that Sigma, "sharp" didn't come around until about f/5.6 and that just wasn't doing it for me nor was it very good even then. Not for that amount of money.
Summary: I love this lens. Super sharp and renders beautiful creamy bokeh. It's bokeh is comparable to the 85mm 1.2 but IMO not as nice. It also focuses really fast and accurate and is light. I mainly use for head shot photography. I have done a review comparing the sharpness and quality of bokeh to the Canon 70-200 2.8.
Summary: I looked for this product because of its fame: sharpness, bokeh. I own already 24-70 I, 24-105, 100 macro. I must say that owning this lens now, everything confirms: astonishing sharpness and a very pleasant bokeh, especially in close portraits. I am not disappointed at all. A high class Canon product if the focal suits you.
Conclusion: Portraiture is everything to me and I love working the streets with this lens and my 5D3, My only complaint is that Canon choose to use a plastic filter thread on this lens,Extra care must be given to prevent crossthreading. As for weatherproofing, How many folks shoot portraits in the rain? As for IS, I seriously dont believe that the same image IQ could be maintained by adding extra lens elements that IS would require and then pay extra to boot?
Summary: After reading too many long, and arduous threads pertaining to the new Zeiss 135, I felt compelled to share my perspective on the wonderful Canon 135. For my purposes, this is a spectacular lens. I need fast auto-focus, predictable focus lock and natural, vibrant color rendition. This lens provides all of these requirements. Do I wish it were manufactured with metal? Sure, that would be swell...but it doesn't matter with regard to how it performs.
Summary: This is one of the sharpest lens i've ever owned. It's not the most versatile lens, but it's very great for tight portrait shoots; background blur is creamy IMO; one of the best 'bokeh' lens. Image quality is great, it is tack-sharp wide-open even though for partraiture, a little bit of softness is needed. Built quality is wonderful, focus ring is well-damped. The only reason i sell this lens is because of versatility.
Pros: Image quality, build like a tank, focus ring, weight