In late September 1999, I got my hands on the prototype 600mm f/4.0L Image Stabilizer lens and had the opportunity to field test it for 3 weeks. To say the least, I was most impressed. With its lighter weight (11.8125 pounds) and shorter minimum focusing distance (18 feet), I would have--as a full time working professional--purchased this lens even without the remarkable new tripod-sensing image stabilizer technology. In addition, the lens is reported to be the fastest focusing 600mm autofocus lens ever manufactured, by anyone. My brain, however, cannot measure micro-seconds, but I absolutely loved the lens. Another plus: manual prefocusing is available at all times. If, for example, you are using the lens with the 2x (where the light lost to the multiplier increases the time of initial focusing acquisition tremendously), you can simply focus manually (even when in AI Servo mode) until the subject is in relatively sharp focus and then activate AF and let it take over. Nine out of ten times, focus acquisition will be instantaneous.

As for the IS technology, I truly believe that the new IS super-telephotos will blow the socks off the photographic world, and may possibly put Nikon years behind yet again. After shooting more than 60 rolls of film with the tripod-mounted lens with the IS feature turned on (the lens manual incorrectly advises that IS be turned off when the lens is mounted on a tripod), I was amazed that I had made many sharp images of birds with the 2X tele-extender at shutter speeds as slow as 1/90 of a second, and some sharp images with the 1.4X teleconverter at shutter speeds as slow as 1/30 of a second, the latter something that I was never able to do with the original 600 f/4.0L lens. By using the new Fuji film, Provia F, and pushing it one stop, the 1200mm focal length (600mm plus 2X TC) becomes a viable bird photography set-up in most lighting conditions. Astounding. Then, I made a series of huge-in-the-frame (full) moon shots with stacked multipliers (the 2X on the lens and the 1.4X on the camera separated by a 12mm extension tube). They were sharper by far than similar images produced with the old 600. In fact, they were amazingly sharp.

I have not yet had a chance to see how the IS technology works in conjunction with mirror lock and very slow shutter speeds, but look forward to doing so at Bosque Del Apache NWR in NM early this winter.

As much as I love the lens, there were two minor problems:

1. With the lens designed with the tripod mount too far to the rear of the lens, the rig is front heavy so that rotating the lens barrel from horizontal to vertical (or visa versa) in the tripod collar is a bit difficult. (The weight of the front of the lens causes increased friction between the lens barrel and the tripod mount.) With the old 600, you simply loosened the locking button and easily and quickly rotated the lens barrel by rotating the camera with your right hand. With the IS version, the lens barrel rotates more easily if you lift up the front of the lens with your left hand while rotating the lens barrel while holding the camera body with your right hand. This arrangement slows you down a half-second, but in nature and sports photography, a half-second can seem like a lifetime.

2. The manual focusing ring was a bit too stiff for my taste.

As for the other new lenses in the series, I am sure that they are all wonderful additions to the Canon lens lineup, but the IS benefit for bird photographers will most likely be greatest in the 600mm and the 500mm focal lengths. (I plan on purchasing the 500mm IS (approximately four pounds lighter than the 600 IS) early next year; this lens should prove deadly when used with the 2X TC.) Sports photographers--who usually work on monopods--will quickly embrace this new family of lenses and white lenses will once again dominate the sidelines at major sporting events around the globe. Ands lots of wildlife photographers will be walking around with big smiles on their faces and sharper images on their lightboxes.

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