12-18-2011, 10:21 PM
[quote name='Sylvain' timestamp='1324246748' post='13880']
Is this change of blur towards the borders an effect of field curvature or something different ?
[/quote]
This is a combination of vignetting (cat's eye) and astigmatism (uneven tangentially and sagittally resolution).
A common problem of extreme aperture lenses actually.
Is this change of blur towards the borders an effect of field curvature or something different ?
[/quote]
This is a combination of vignetting (cat's eye) and astigmatism (uneven tangentially and sagittally resolution).
A common problem of extreme aperture lenses actually.