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11.1& &&&&&&&&RF28-70mm&F2&L&USM&
RF28-70!F2! L!USM!is!a!large-diameter,! standard!L! zoom!lens! with!a! bright! F2.0!constant!aperture!across!
the!entire!zoom!range!—!the!new !28-70m m!F2.!!!The!lens!is!intended!for!professional!photographers,!
high-end!amateurs,!and!low- lig h t!moviemakin g .!!It!embod ies !high-speed!auto!focus! fun ctionality,!and!a!
Control!Ring!for!functional!assignment!of!exposure!controls.!
!!!!!!!!!!!!!!!!!!! !
Figure&12!!! The$new$RF28-70$F2$L$USM$—$a$compact$28-70mm$F2.0$zoom$lens$has$high$overall$
optical$performance$and$excellent$operational$empowerments$
The!lens! is! comprised! of! nineteen! elements! in! thirteen! groups.! ! The!large!diameter!moun t! and!the!short!
back!focus!are!used!to!particular!advantage!to!gain!the!higher! brig h tn e ss ! of! F2.0.!! !Th ese!two!factors!
mean! the! front! section! of! the! lens! can! by! physically! much! smaller! th an! conventional! EF! lens!
architecture.!!The!strategic!disposition!of!four!aspheric! lens!elements!(shown!in!light! green)! in!Figure!13!
helps!to!minimize!astigmatism,!spherical!aberration!and!geometric!distortion,!while!the!two!UD! and!o ne!
Super!UD!elements!(dark!green)!help!curtail!the!longitudinal!and!lateral!chromatic!aberrations.!
!
!!!!!!!!!!!!!!!! !!!
Figure&13&&&&&&There$ are!thirteen $groups$made$up$of$a$total$ of$nineteen$lens$elem en ts$in$the$RF28-70mm$
F2$L$USM$lens$
14!
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