| Year | 1978 |
| Lens Groups | 7 |
| Lens Element | 7 |
| Aperature Blades | 9 |
| Minimum Aperture | f/32 |
| Closest Focusing | 3. m |
| Max. Magnifcation | 1:9.1 (0.11x) |
| Filter Size | 34 mm |
| Diameter x Length | 85 x 208 mm |
| Weight | 1235 gr (2.72 lb) |
| Hood | - |
This is a fabulous lens. I use it on Panasonic Lumix GH1 and G1 cameras, on which it becomes a very light-weight 600mm equivalent. The image quality remains high with the Canon 1.4x-A extender and isn't bad with the 2x-A extender. There's no problem shooting it wide open. With my Lumix cameras I'm using the central (best) area of the lens, so I have no vignetting and little loss of sharpness toward the edges. I rarely use it hand-held. Most of the time it's mounted on a Kirk King Cobra gimbal head and a heavy-duty Gitzo tripod to photograph birds and other wildlife. I even use it to shoot photos of flowers and other close subjects.
My other birding setup is a Canon 7d with a 300mm f2.8 Canon IS lens. It's a great system as well, but it weighs much more and costs about five times as much. And the image quality isn't any better. It's primary advantages are image stabilization and a larger sensor.