Boat -- NEX-5N & Canon FL 50mm f.14 @ f1.4, ISO 1000
The Canon FL mount was the predecessor of the Canon FD mount. Basically, it's a very simple mount without any sort of automation, such as aperture priority or speed priority. All these are really the same mount. Most FL lenses will work on FD bodies as with stopped-down metering. I did try the FL 58mm f1.2 on the Canon T90 and it worked well. The Canon FL 50mm f1.4 lens has the same build quality as the FL 58mm f1.2. Both lenses have the A/M switch for manual aperture control. This feature was removed from the later FD and New FD mounts.
Red Tulips -- Panasonic G1 & Canon FL 50mm f1.4
In terms of optical quality, it's slightly less sharp wide open than the FD 50mm f14 SSC or the nFD 50mm f1.4, but is still usable. Lots of purple fringing at wide apertures on scenes with strong back lighting, but improves when stopped down. There isn't too much difference between f4 and f8. All three mounts of this lens are excellent when stopped down a little. I find the colour of the FL 50mm f1.4 to be very neutral, compared to the FD and nFD versions.
In all, I like this lens. When you hold it in your hands, you feel the quality of the all metal construction. The 8-blade aperture helps this lens' nice bokeh. I don't see too many of this lens, but lots of the cheaper, but not any less well made 50mm f1.8 version, which is also a nice lens. All the FL lenses I have were made with quality regardless of class. The FL 50mm f1.8 feels just as good as the FL 58mm f1.2. For us manual focus lens addicts, a well made lens is just as important as its optics. In this department, the FL lenses deliver, and their optical quality is not too shabby either. Grab them if you see them cheap.