You make it sound like elements are added in order to increase aberrations. Why would a lens designer want to do that? In fact the opposite is the case. All the best! Raimo Personal photography homepage at http://www.uusikaupunki.fi/~raikorho
-----Alkuper�inen viesti----- L�hett�j�: Keith Whaley <[EMAIL PROTECTED]> Vastaanottaja: [EMAIL PROTECTED] <[EMAIL PROTECTED]> P�iv�: 22. tammikuuta 2003 21:07 Aihe: Re: Vivitar 35-85 better than Pentax 24-90? >You're absolutely right, J.C. >Each added element adds two more medium interfaces (air-to-glass, >etc.) and each have their own abberations, no matter how small, to the >whole. The more elements a lens assembly has, the more perfect each >and every lens in the whole assembly has to be, to the point where to >be the 'best,' each element has to be hand-figured to match or >compensate for all the others. To work together well, as it were. > >"J. C. O'Connell" wrote: >> >> It's still true today, all else being equal, a lens design with >> less elements will be sharper and more contrasty than one with more. >> For a given focal length and speed, there is an "ideal" number >> of elements to optimize the design. > >I was unaware of that. Is there a list or chart somewhere, or a >discussion about this I could read? >Thanks for pointing that out. > >> More does NOT always equal better when it comes to lens elements. >> JCO >> >> > -----Original Message----- >> > From: Raimo Korhonen [mailto:[EMAIL PROTECTED]] >> > Sent: Wednesday, January 22, 2003 12:26 PM >> > To: [EMAIL PROTECTED] >> > Subject: Vs: Vivitar 35-85 better than Pentax 24-90? >> > >> > >> > It used to be so before World War II because of un-coated lenses >> > - but not anymore, even less with multicoating. Not many >> > single-element designs around ;-) >> > >> > Raimo > >[...] >
