| Year | 1974 |
| Lens Groups | 11 |
| Lens Element | 15 |
| Aperature Blades | 8 |
| Minimum Aperture | f/22 |
| Closest Focusing | 2.5 m |
| Max. Magnifcation | 1:6.8 (0.147x) |
| Filter Size | - |
| Diameter x Length | 94 x 243.5 mm |
| Weight | 1695 gr (3.74 lb) |
| Hood | - |
This is a very useful lens for video work and still photography as long as you don't mind the size and weight and are willing to use it at apertures from f6.3 to f11. Wide open it's pretty bad.
The zoom and focus rings operate very smoothly, which works in favor of the lens for video useage. I use mine on a Panasonic Lumix GH1 camera, on which it becomes effectively a 170-600mm lens. It's great for wildlife and birds as long as you have enough light. When shooting video the shutter speed is best set to 1/30 to 1/60 second in most cases. At those settings, the small apertures become less of an issue. I mount the lens on a Kirk King Cobra gimbal head and use a heavy duty Gitzo tripod.
I bought this lens only because it was too cheap not to. £26 for a lens that I'd coveted years earlier priced in the hundreds of pounds! It came to me needing a major clean but under all the muck it was in very decent optical condition. I still had to find a tripod mount, but was lucky enough to find it on eBay so it is now complete.
I've carried this lens around a couple of times and while it's a brute it's not that much different to the modern EF70-200L f/2.8 which many carry without batting an eyelid in these days of equipment bloat. It is a touch soft and low contrast but given the age of design and the range and fast max. aperture it's not as bad as I had feared.