Hi, Ramesh I will look into each lens more closely as time allows. For this first test I used only two apertures.
How much each lens needs to be stopped down is indeed an interesting question. Another is how much diffraction will impact the quality when stopped down fully. More later. Jostein ----------------------------- Pictures at: http://oksne.net ----------------------------- ----- Original Message ----- From: "Ramesh Kumar" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, October 27, 2003 1:14 AM Subject: Re: Tests of chromatic aberrations with *istD > Informative test. > I have question aboutt FA 100mm f2.8. > Do you know at what aperture abberation disappears? > > > Thanks > Ramesh > > --- Jostein <[EMAIL PROTECTED]> wrote: > > Gang, > > I have tried to sum up some experiences from the > > first two days of shooting > > with the *istD and various lenses on a webpage: > > http://home.online.no/~jooksne/istd/aberration.html > > > > No big images, but lots of crops. Shouldn't load too > > slowly, though. > > > > There's a big table in there which will be too wide > > for many screens, I > > know, but it was what I ended up with, and I'm too > > tired to recast it now. > > Sorry about the inconveniece and hope you can > > cope... > > > > For those who don't bother, here's a brief > > conclusion: > > > > I couldn't detect any chromatic aberrations in any > > lens when stopped down > > to f/8 or f/11, except the FA*400/5.6. > > > > For wide open apertures i found: > > The FA*28-70/2.8 is one bloody good lens! > > The FA 28-70/4 is poor in terms of sharpness and > > contrast, but has no > > aberration. > > The FA 100/2.8 macro has clearly visible > > aberrations. > > The FA*400/5.6 has moderate aberrations, that > > doesn't go away when stopping > > down. > > > > Sigma APO 70-200/2.8 has bad aberrations at 70mm, > > but not at 200mm. > > > > Cheers, > > Jostein > > - > > > > > __________________________________ > Do you Yahoo!? > Yahoo! SiteBuilder - Free, easy-to-use web site design software > http://sitebuilder.yahoo.com >
