1 extreme aspherical, 3 fluorite, 2 extra low dispersion
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The Digital Picture
It is arguably the sharpest 600mm interchangeable camera lens ever produced. This superbly-designed, ultra-light weight lens performs extremely well, making it a perfect choice for advanced amateur and professional wildlife and sports photography and photojournalism. I would have been happier if OSS performed better in my testing and vignetting is slightly higher than in the competition.