Hi Bart,
To reveal a nice trick for when you need a fast output with very decent sharpening at the native pixel dimensions, you can output an unsharpened magnified/scaled filesize, apply Focusmagic at that magnification (C1 goes to 250%), and then downsample with bicubic in Photoshop (not ideal, but quick) to the normal pixel dimensions (40% of 250%). The only FocusMagic limitation in combination with Photoshop CS6 seems to be a 2GB filesize.
Would this magnification need to be done in the raw converter? My raw converter has no such option.
Hi Hening,
No, FocusMagic only processes images that have already been demosaiced. So you can do that on the output file of your Raw processor of choice. Just make sure you apply no (or
very little) sharpening at the Raw stage at all.
The reasoning behind it is that upsampling that unsharpened data will have a kind of low-pass filtering built in that will prevent aliasing artifacts when downsampling back to the regular size again. The upsampling itself tends to anti-aliase edges that are bordering on stairstepping/aliasing themselves. The sharpening of the upsampled data will not produce pixel perfect sharpening, but will boost 'micro'-contrast and resolution which is now probably multiple pixels large.
Downsampling that enhanced micro-contrast will attempt to create downsampling artifacts (due to the imperfect bicubic filterering), but there will probably be not enough really high frequency detail to cause much of a problem, just better contrast and some restored resolution at the magnified sub-pixel level.
But I could magnify in PhotoLine, where I could use Lanzcos 3 or 8 for both the up- and down scaling - assuming this would be better than bicubic (speed is no worry).
Upsampling with Lanczos is not recommended without a means of regularization of the ringing that is inherent in that type of filtering. Otherwise I'd rather use something more subtle like Mitchell Netravali, if that's available in Photoline. Downsampling may be better when Lanczos 3 is used, but watch out for ringing artifacts near sharp edges on uniform backgrounds. We wouldn't want the quick and dirty to become very dirty ...
Cheers,
Bart