Continued from reply #217
Attached you will find screen grabs at 300% (and therefore pixelated) of the Original unsharpened Raw conversion with CaptureOne Pro, and FocusMagic restored versions. The first screen grab shows that there is very little contrast in the finest details (even in Green), which suggests that the lens is struggling. Diffraction does not help, so it might be possible to improve that micro-detail contrast by using a wider aperture, but then obviously there will be less DOF, unless one resorts to focus stacking.
The first screen grab shows the result after using FocusMagic with a radius setting of 2, on a duplicate layer in Photoshop, because a smaller radius has less effect, and 3 creates ringing artifacts. A good method to achieve the optimum radius setting is to start with an overdone Amount setting of 300%, and then slowly increase the Radius. There will be an increasing effectiveness, until suddenly there will apprear 'fat' edges instead of sharper edges. That's the signal that one needs to step back 1 Radius unit.
Very sharp lenses can require a Radius of 1, and not more, but 1 or 2 are common values for detail in the plane of optimal focus.
The FM sharpened result looks too contrasty, and a bit blocky (part of which is because of the 300% screen zoom), but there are no obvious edge halos. That means that the Radius setting was indeed optimal. However, the image does not look very organic anymore, so it seems to be pushed too far (amount to high). But I did that for a reason, with the following modifications in mind.
The FM deblurring was done on a separate layer, because that allows to use two useful adjustments. The first adjustment is to turn the layer
Blend If mode into the following basic settings (which can be tweaked for further refinement):
This Blend-if setting is based on the following assumptions. When edge contrast is very high already, additional sharpening can cause clipping on images that span the full brightness range, and because the contrast is already high, more contrast is not really needed. Therefore we gradually reduce the increased edge contrast effect the closer we get to the extremes of edge contrast. We also use a Luminosity blending mode to reduce the risk of color shifts caused by the boosted contrast. This already takes away some of the initial harshness, and the start and end of the transition zones can be tweaked for even smoother or more sudden transition. The initial 127/128 switch is a good starting point, so I just used that for simplicity. It is also possible to use a Photoshop action to create a duplicate layer and set the layer blending mode and invoke FocusMagic with a single click to play the action.
The second screen grab attachment compares the straight FM deblur, with the Blend-if version, and I also added an 85% opacity to the layer to let some of the original smooth transitions to blend in. That opacity setting is also a matter of taste, and depends on the subject matter, so use you imagination.
The Blend-if layer also tends to reduce noise that may be accentuated by sharpening, although Focus Magic attempts to not boost noise as much as detail.
To be continued...
Cheers,
Bart
