[quote name='mst' timestamp='1297407266' post='6052']
I'm pretty sure it's not <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='
' />
-- Markus
[/quote]
The curve has a very pronounced wave form with a sub-wave and at f/2 there's simply a sub-wave top at the border test zone. The sub-wave moves out when closing the aperture (thus increasing the quality in the center zone) and a local low enters the border test zone at f/2.8. I we took -say- ~5 center-to-border readings this would probably get more obvious but that's an overkill.
Focus shift is not an issue in our test procedure.
I'm pretty sure it's not <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='
' /> -- Markus
[/quote]
The curve has a very pronounced wave form with a sub-wave and at f/2 there's simply a sub-wave top at the border test zone. The sub-wave moves out when closing the aperture (thus increasing the quality in the center zone) and a local low enters the border test zone at f/2.8. I we took -say- ~5 center-to-border readings this would probably get more obvious but that's an overkill.
Focus shift is not an issue in our test procedure.