Warren, Connecticut. I’ve now done some more testing of the Canon 200mm f/2.8 L lens vs. the Canon 135mm f/2 L lens plus Canon 1.4x extender and while there are some differences, they’re not enough to warrant buying the 200mm lens (which is a great deal).
When you add the extender to the 135mm f/2 lens you get a 189mm f/2.8 combination. Not quite 200mm but the same speed. While my tests are informal I’m happy with both the sharpness, color, bokeh and handling of the 135 and extender. Is the 200mm better? Probably, but not enough to warrant buying it in addition to the 135.
I like the shape of chemistry glassware and I’m going to order some more to use as subjects for photographs.