Thanks Rob, very informative. I must admit to never really noticing CA in the past unless present at the plane of focus, I SHALL be looking in the future.
John ---------- Original Message ----------- From: "Rob Studdert" <[EMAIL PROTECTED]> To: [email protected] Sent: Wed, 05 Jan 2005 00:39:07 +1000 Subject: Re: PESO" New Year's Day Walkaround > On 4 Jan 2005 at 10:55, John Whittingham wrote: > > > > it seems relative to the distance from the focal > > > plane like a severe Longitudinal Chromatic Aberration (LCA). > > > > Would this not be evident on all telephoto lenses to some greater or lesser > > degree? > > Sure but lesser or non-evident is more desirable of course. ED > elements have been employed in Pentax lenses in order to reduce LCA > and TCA and in their long fixed FL lenses it seems to do a good job > to pretty much negate visible CA. > > Looking back at Pauls shot again it's sharp and contrasty but the > blue/yellow fringing around the twigs to the right is quite obvious > (despite the relatively small image dimensions). Unless the image > was a 1:1 crop of a high res scan I'd suggest it is excessive and > I'd be a bit disappointed as it would have spoilt the shot for me. > > Rob Studdert > HURSTVILLE AUSTRALIA > Tel +61-2-9554-4110 > UTC(GMT) +10 Hours > [EMAIL PROTECTED] > http://members.ozemail.com.au/~distudio/publications/ > Pentax user since 1986, PDMLer since 1998 ------- End of Original Message -------
