Hi Bart,
My experience is more a bit like your diagram. I see some maximum in sharpness, but it is more at the 2cm level at 4.0 meters than on the mm level.
Regarding "standard sharpening" in Imatest, it may be a red herring. I wrote Norman Koren about it, asking if it was an indication for good or adequate shrapening, an he cautioned about it.
My experience is that I can apply a large amount of sharpening at small radius and still have undersharpening according to Imatest.
To understand Imatest "standard sharpeinung" it may be helpful the read the relevant information at Imatst:
http://www.imatest.com/docs/sharpening/My take on the issue is that Imatest assumes a sharpening that will result in MTF 100% at 0.3 x Nyquist frequency. When we sharpen at actual pixels we tend to sharpen with a large amount at small radius. This will enhance "micro contrast". But, that "micro contrast" will normally contribute very little to perceived sharpness in a print, as medium frequency detail will dominate.
If I push pixel level sharpening in Lightroom and analyse in Imatest I will always end up with under sharpening. On the other hand I can try some more balanced sharpening like the "high frequency/landscape" presets in Lightroom and apply some sharpening say 15% at radius 2 in Photshop unsharp mask, and that will be pretty good sharpening according to Imatest.
Using "landscape" sharpening and say 15% unsharp mask at radius = 2 will give excellent SQF values in Imatest.
Focus magic gives pretty optimal results in Imatest. No MTF above 1.0 in 0-0.3 Nyquist, MTF near 1.0 at 0.3 Nyquist and a decent level of MTF at Nyquist. Also, FocusMagic doesn't enhance noise as much as many other methods of sharpening.
As a side note, the "Orange Peel" artefacts "Diglloyd" has found may be a sharpening artefact, possibly combined with aliasing. What I may have seen is that sharpening using FocusMagick will not cause some artefacts which may be the foretold "orange peel" artefacts.
So, I would say that I really appreciate FocusMagic, it is one of the best tools I have found for sharpening. But, it doesn't fit my parametric workflow. Would I do a large print, I would probably deploy FocusMagic and some other tools, but for 90% of my work I try to get around with the tools provided with LR 6.
Now, getting back to MFD, what I have seen is that there are no magick differences between my MFD gear and my Sony Alpha 99 gear. The great advantage of MFD I see is resolution, but that advantage takes like A1-size prints to show up, unless I view my images with a loupe.
I am pretty sure that those 80MP backs, paired with excellent lenses, have a resolution advantage over present day high MP 135, even if the best lenses are used. With lesser backs, say 40-50 MP I am a bit skeptical.
One interesting observation is that a frquent poster here in LuLa, Chris Barret, shifted over his work from IQ-260 (I think) to Sony A7r. He uses it with Canon T&S lenses and Hasselblad CFi glass, pretty much what I have. He feels that the old Hasselblad/Zeiss glass works very well on the A7r.
Rainer Viertlboeck, a well known German architecture photographer is also quite happy with the A7r:
http://forum.luminous-landscape.com/index.php?topic=90358.0So, it seems that real commercial photographers see real benefits with high MP 135.
Personally, I have been shooting my A7rII for just three weeks so I don't feel I can make a lot of comments.
Best regards
Erik
Hi Eric,
I also did similar tests (see attachment), using a Stackshot rail at some 3.34 metres distance on a slanted edge target, to find the best/highest focus/resolution possible at various apertures, as a prelude for deconvolution sharpening. In my findings I did not observe a (sharp) peak, but a gradual optimum (which is what I expected because defocus blur does not change focus abruptly, but rather more gradual).
I don't see why it would. After all, all that happens when we focus, we make the focus plane intersect the exit pupil's cone of rays at slightly different positions. That cone of rays has a constant acceptance angle for each focus point/sensel, so equal steps will show a gradual increase/decrease. When the same focal length and aperture are used, then the size of the sensors makes no difference, the cones are basically the same.
Cheers,
Bart