Yes, Many years ago, When I first get my Big 600 mm Canon Lens, The Fist that I see after open the Brown Paper Box = The Beautiful Canon Lens Box( Please see the Photos), and The Beautiful Canon , original Lens Cap = $ 125 US Dollars, Yes , after the First use of my beautiful 600 mm. Canon Lens,Both of The Original Case and the Original Lens cap are big and Clumsy, I just Pack the Original Lens Case and Original Lens cap in the Brown Box, and Never use them again, Yes, I Get Tenba LL, 600 mm. Lens Bag( 180 US Dollars), and Don Zack 600 mm. Lens Cap( $ 60 US Dollars ), and never look back to the original Case and Cap anymore.
Here is the link of the Great Don Zack Lens cap for most of the Long Tele. Canon Lenses.http://www.donzecklenscap.com/
Enjoy my complaints.
"Smart Design, Great Craftsmanship
Jan 25, 2011 by: Surapon Sujjavanich
YES, I just get your Don Zeck Lens Cap # 10 yesterday for my Canon EF 600 mm. F/ 4.0 L IS USM, and this cap is the most SMARTEST DESIGN and GREAT craftsmanship—Yes Follow Functions as the Old Master Said. Beautiful Craftsmanship, Light weight material and perfected Fit to my Lens. Yes the O rings are Very Smart Design, to fit the cap on the front of lens perfectly with out touch the high cost of glass. The Design + Craftsmanship of this Lens cap = A++ Surapon Sujjavanich, AIA, CPS."