This is one of my favourite lenses. I was over joyed when I acquired this lens a few years back and used it extensively. I didn't have a lot of manual focus lenses back then. Gradually, I got more lenses, and this one (two actually) was neglected and have not seem much use lately. In any case, along with the Carl Zeiss Jena Sonnar 200mm f2.8, they are the two lenses that I considered great lenses.
This is a rare lens in North America. You don't too many of them here, but more abundant in Europe. For this reason, it's a very sought after lens.
First thing first, the aperture in this lens is very easy to break. Both of my CZJ 80/1.8 had problems, and I sent one of them to China to have a part made in order to get the aperture to work again. The other was cleaned and fixed by Andrei.
Second thing is that like many older lenses, minimum focusing distance tends to be long at 0.83 meters (almost 3 feet), and the magnification factor is rather small. Don't know the exact ratio but not very good for close ups. The CZJ 200mm f2.8 has the same problem.
Other than the above, the lens is very well made. All metal construction and focusing is very smooth.
Image quality. Before I got the lens cleaned, there was a layer of very fine dust inside, making it very prone to flare and wide open was not very sharp and had very low contrast. But after one stop down at f2.8, it is excellent. After it's cleaned, the difference is like day and night in wide apertures. SHARP at f1.8 and absolutely usable. The colour tends to be neutral, but pleasing. Very similar to my Leica Summicron 90mm f2 (TWO CAM version). The colour, of course, is very dependent on the camera used. On the original 1D, which uses a CCD sensor, the colours are more vibrant than the other Canon DSLRs that use CMOS sensor. The bokeh is very nice too, despite the 6-aperture blades.
Over all, a nice lens to keep and a enjoy to use. I sold one them, but I will not sell the remaining one.