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Joined on May 18, 2004


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In reply to:

Joseph S Wisniewski: You folks have no idea how much "wow" is in a T2.9 zoom like that.

70-200 parfocal (no focus shift when zooming) and hopefully no breathing (coverage shift when focusing). It's got to be at least as complex as any Nikon or Canon 70-200 f2.8. You're taking 20-something elements, and a light loss of 0.1 stops (weird coincidence, log2((2.8/2.8)^2) = 0.10)

Most elements in a modern lens aren't cemented, but let's do worst-case and guess that some are, so there's 30 air-glass interfaces (surfaces, LOL). That's 0.0033 stops per surface. Or under 0.8% reflection per surface.

That's some serious coating.

Do we know that it's an f/2.8 and not, say, f/2.5? A .10 stop light loss with 20 or so elements seems insanely low.

Link | Posted on Apr 17, 2012 at 14:42 UTC

Are the Japanese averse to viewfinders? This is getting absurd.

Link | Posted on Apr 5, 2012 at 23:09 UTC as 22nd comment | 13 replies
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