[Tiz]

I understand that most of the blur caused by an AA filter can be reversed by using more sharpening (compared to a body w/o an AA filter).



Does the same principle apply to lenses (i.e., can a large amount of the blur cause by a low-resolving lens be compensated by additional sharpening)?



Thanks.

[Klaus]

[quote name='Tiz' timestamp='1291842510' post='4878']

I understand that most of the blur caused by an AA filter can be reversed by using more sharpening (compared to a body w/o an AA filter).



Does the same principle apply to lenses (i.e., can a large amount of the blur cause by a low-resolving lens be compensated by additional sharpening)?



Thanks.

[/quote]



No, the diffusion caused by the AA filter is much less pronounced than on a mediocre lens. Basically a AA filter diffuses by a factor of 1.1-1.3x which can be recovered by sharpening because this is still a diffusion on sub-pixel level. However, beyond that the diffusion is really lossy. A bad lens blurs across -say- 3px or more in the corners (thus resolving only a fraction of the potential resolution).

[Brightcolours]

[quote name='Tiz' timestamp='1291842510' post='4878']

I understand that most of the blur caused by an AA filter can be reversed by using more sharpening (compared to a body w/o an AA filter).



Does the same principle apply to lenses (i.e., can a large amount of the blur cause by a low-resolving lens be compensated by additional sharpening)?



Thanks.

[/quote]

Yes, the same principle applies to all small causes of unsharpness.



However.



An AA-filter actually enhances the captured image, avoiding the capture to contain false details and frequency related artifacts. It does so in the assumption the lens is delivering a sharp projection.

Any unsharpness extra from the lens gets added to the unsharpness from the AA-filter. Just like a slight movement will add motion unsharpness to the unsharpness of the lens and of the AA-filter. It all adds up.



There is a limit to what you can "sharpen" before sharpening artifacts get to be too intrusive.



Basically, lenses do not need to be "tack sharp" in order to get good results, but there is a limit to just how unsharp they can be.

[genotypewriter]

[quote name='Tiz' timestamp='1291842510' post='4878']

I understand that most of the blur caused by an AA filter can be reversed by using more sharpening

[/quote]

Klaus... [url="http://forum.photozone.de/index.php?/topic/515-comment-on-lenstip-optyczne-article/page__view__findpost__p__4677"]Didn't I tell you[/url] this might happen? <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />



GTW