Sharpening

[patrickh]

I notice many samples with the proud claim "no sharpening" and the assumption that this means the picture demonstrates how sharp the lens is. This is probably correct for film takers, but not for digital sensors. Virtually all sensors have anti-aliasing filters, and one of the by-products of this is to "blur" the picture. When a camera produces a jpeg, the internal software applies sharpening as part of the algorithm, and the strength is often controllable. For RAW, the user must compensate for the blurring by applying some degree of sharpening during processing (I deliberately did not use the phrase "PP"). Can we all agree to be rather more precise when using this claim of "no sharpening"? Bear in mind the sharpening does not create extra pixels or detail, it basically adjusts micro-contrast in a variety of ways, and can easily become just too much, with obvious artifacts. "No sharpening applied" is often very mis-leading by its implication that a good lens does not require sharpening, which is simply not true in the digital world.


patrickh

[Orio]

Very true Patrick.
I think that when people writes "no sharpening" they really mean "no PP sharpening".
Which however does not say much anyway because usually digital cameras offer different levels of in-camera sharpening (if you take JPGs)
and RAW programs usually are not set to zero sharpening by default (if you take RAWs).
I think that if someone has the goal of testing lenses, he should adopt a standard and always go with it.
For instance, leaving his camera's sharpening or his RAW program's sharpening always at the same level.
This will not ensure results that are comparable with photos taken by other photographers, but at least will ensure that the
results obtain by that same photographer are comparable (until he changes camera, that is... )

[Nesster]

...or changes PP routine.

After resizing I always do a .2 pix ~6-10 radius (not critical) @ 180% regardless of original source.
With home scans, I usually do ~3 - 3.4 pix ~34-40 radius (not critical, though at least 10X the sharpening pixels) @ 76 or 80% (percentages picked due to high school and college graduation years). This low frequency sharpening helps my scanner


At least 'no sharpening' isn't like people who say 'cheap film'

[poilu]

[patrickh]

poilu

You are correct, I should have been less strident and said "often" rather than my absolute statement. I suspect that 90% or more of the digital cameras used in this forum have some form of anti-aliasing. I stand by my cry to be much more cautious about using the "no sharpening" claim to enhance a lens' claimed sharpness though.

patrickh

[martinsmith99]

I don't like that claim and so I don't make any comments on sharpening. I have a default value set in ACR that I use 99% of the time and use high pass filter to sharpen sometimes.