The One and Only Dream Super Tele You'll Ever Need
Since the digital age started, nobody talks about telephoto lenses any more. With 35mm, it was all amateurs cared about. I think this is because digital, with its reduced-size sensors and "crop factors," gives telephoto shooters an inherent advantage, so there's less to bitch about. Where's the fun?
Olympus, especially, gives telephoto shooters a real leg up. The slightly-smaller- than-APS-C 4/3rds sensor affords an inherent 2X extension. Back in 1990, sports'n'critter shooters would have wet themselves over a built-in 2X extended with no speed penalty. Now no one cares.
Olympus has also had to build its lens line from scratch. This makes people happy by giving them a lot to bitch about, but not at the telephoto end. Olympus has a 300mm-e (mm-e = "millimeter equivalent") ƒ/2, a 70–200mm-e ƒ/2 zoom, an expensive 600mm-e ƒ/2.8 and an affordable 100–400mm-e ƒ/2.8–3.5. These are almost all specifications that would have satisfied a lens-luster's fantasies back in the day. Ho-hum.
Most impressive, perhaps, is Oly's super-telephoto zoom, the only one most shooters would ever need. It's an amazing 180–500mm-e ƒ/2.8 (actually a 90–250mm). It's a relatively expensive lens, so you won't see it reviewed very often, but the English edition of the Slovenian website e-Photografija has just published a thorough review written by Matjaz Intihar. Translation honors were well acquitted by Joze Sveticic. There's also a new review of the "Canon Cannon," the 400mm ƒ/2.8 L IS USM.