Wow Craig, that what is called professional approach. :-) Appreciate your efforts. I suspect these "micro"-differences are mostly of academic discussions, rather then implied in practice, however I'm glad the 70-200/2.8L USM, I'm in the process of purchase right now, delivers the cutting edge of performance this kind of lens can produce. Of course, having additional 700 $ for this purpose would solve any hesitations purchasing the IS version but we live in real world where there is no meaning for "additional" cash... :-)
I hope you will forgive my ignorance and stupidity, but would you clarify the terms parfocal and varifocal and how it implies on optical quality of the lenses ? Regards, Alex Z -----Original Message----- From: [EMAIL PROTECTED] [mailto:owner-eos@;a1.nl]On Behalf Of Craig Zendel Sent: Tuesday, November 12, 2002 10:55 AM To: [EMAIL PROTECTED] Subject: Re: EOS 70-200/2.8L against it's IS brother ----- Original Message ----- From: "Alex Zabrovsky" <[EMAIL PROTECTED]> To: "EOS list" <[EMAIL PROTECTED]> Sent: Monday, November 11, 2002 1:18 PM Subject: EOS 70-200/2.8L against it's IS brother > Just read on certain website that the 70-200/2.8L USM IS is somewhat > superior to it's predecessor > (no IS) in terms of optical quality, even though having more internal > elements. > Can somebody confirm that ? Did they really further enhanced optical design > producing the IS version so it is even better optically then the regular > version ? Alex, I did a side by side comparison of these. If you search the archives you will more comprehensive results. I found the non IS lens to have very slightly better microcontrast/sharpness wide open, by f/4 the results were indistinguishable. This was confirmed by collimator tests at Canon UK. I chose to keep the IS version on the grounds that I was prepared to trade off the open aperture performance for the IS function. The IS lens will get the picture when the non IS can not. As you know the 70-200 IS is one of, if not the most complex, of any Canon lens and as such I would expect it to have more build variables than less complex designs. A recent conversation with a Canon UK technician reinforced this opinion, when I pointed out that my lens is not a true parfocal zoom but is slightly varifocal. I was told that this can be rectified by swapping out the lens mount until one is found that is the exact thickness. I was assured that the optical performance is not affected, but ??????? HTH Craig Z * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
