>----- Original Message ----- >From: <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Sent: Friday, December 13, 2002 10:30 AM >Subject: RE: EOS Lens Test >
>> There is an interesting site at http://www.dforum.de/ >> which has lens tests made using D60s for testing! >> Does anyone understand their technique? What do ?> the red and green dots mean? > >It wasn't obvious to find, but I think you mean this page: >http://www.dforum.de/Technik/Objektivtest/obj-test02.htm > >The red dots indicate the point of highest visible resolution in pairs of lines mer mm per position per aperture (different >graphs for centre and corner of the picture). >The green dots indicate where the contrast of the black lines still reaches a 50% gray value... > >Note that the creators of this test tried to standardise a cheap and simple method of determining lens quality >ESCPECIALLY for digital purposes. > >Cheers, Stefan > My German is poor so some of my comments may be covered in text on the site, but I find it quite amazing that the newer EF 100 USM macro seems to show very much lower resolution at the 50% contrast point than the earlier version. I owned both together for a short while, and whilst I didn't do any side by side tests, I certainly haven't noticed any obvious difference between their results. The USM version is certainly easier to use. I wonder if they used any lens hood? The earlier lens front element is quite well shielded if used without a filter or lens hood; whilst the front element on the USM version is exposed and the dedicated Canon lens hood for it is quite deep. Similarly it would appear (50% grey again) that we would be nuts to spend money on the 50 f1.4 if we already have the 50 f1.8. I wonder if the test charts which the different testers use are correctly optimised for different printers / gamma considerations. Perhaps their command of Norman Koren's English text accompanying his charts for download is as bad as my knowledge of German! Unlikely I would expect but .... (I use Provia 100F on an EOS3.) Any other views? Malcolm Milton Keynes, UK * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
