On Tue, 19 Oct 2004 10:01:47 +0200, Dario Bonazza <[EMAIL PROTECTED]> wrote:
> Perspective is not aberration (any lens of a given focal length will show > the same perspective), unless it's a shift lens. or unlsess it's a lens on bellows. > Distortion is a geometric aberration. It is not influenced by stopping down, > but can be influenced by diaphragm position within the optics. A fish-eye is > an ultra-wide angle lens whose distortion has not been corrected > (intentionally). A rectilinear is a lens whose distortion has been > corrected. botyh, fisheye and rectilinear distort, just differently. one with "tg x" and the other with "sin x" or plain "x" distortion. 12mm rect lens distorts no less than 12mm fisheye. but in a very different way. mishka > > Dario Bonazza > > ----- Original Message ----- > From: "Raimo K" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Tuesday, October 19, 2004 7:53 AM > Subject: Re: Long zoom recommendations > > > Stop laughing. Distortion is not an aberration. By distortion you describe > a > > situation when e.g. straight lines are not reproduced straight. > > "Distortion: Causes image of window frame (for example) to bow out (barrel > > type) or in (pincushion type), but does not influence sharpness. Not > > improved by stopping down." Lens test glossary, Popular Photography, > > September 1984. > > All the best! > > Raimo K > > Personal photography homepage at: > > http://www.uusikaupunki.fi/~raikorho > > > > > > ----- Original Message ----- > > From: "Rob Studdert" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Tuesday, October 19, 2004 6:52 AM > > Subject: RE: Long zoom recommendations > > > > > > > On 18 Oct 2004 at 23:26, J. C. O'Connell wrote: > > > > > > > I don't think "outside the box" when "inside the box" is the preferred > > > > method. > > > > I cant think of a single instance where I have read > > > > anything regarding optical "distortion" where they were > > > > > > Surely you can't be that closed minded? Distortions are aberrations. LOL > > > > > > 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 > > > > > > >
