Tell you what, Bill, take out that zoom and a prime of the same f-stop. Use an external meter to set the exposure for both of them. Examine the unprocessed images closely, then get back to us with the results. Multi-coatings help, but I do not think they completely eliminate the problem. It is the fact that metering is now done mostly BTL (behind the lens) that has made this pretty much unnoticeable. Current zooms with their multi-coatings, aspherical elements, and extra-high-dispersion glass minimize the effect, but once again I do not thing they completely eliminate it.
-- graywolf http://www.graywolfphoto.com http://webpages.charter.net/graywolf "Idiot Proof" <==> "Expert Proof" ----------------------------------- William Robb wrote: > ----- Original Message ----- > From: "Igor Roshchin" > Subject: Re: Seen on eBay > > > >> I think the author meant to say that zoom lenses more often than prime >> lenses tend to be soft when wide open. So, if you have a zoom lens, >> and want the best quality, you'd need to stop it down. Hence, >> such a zoom is effectively slower. > > There used to be an urban legend that zooms were slower than their marked > speed because of light loss due to absorbtion , internal reflection and > flare. > There was probably some truth to it with the early zooms too. > > William Robb > > > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
