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| p.32 #5 · Still no love for the Ricoh GXR? |
I find it interesting that in Matt's house pics, the one at f/11 looks pretty much like what one would get at f/5.6 with AA. Since I started using AA cameras, my smallest aperture became f/8, while in the past I had no problem shooting at f/16 regularly. So I think this is something additional to consider that one can shoot at smaller apertures without AA, get rid of moire, get more DOF, and still be within the sharpness performance of an AA cam.
A camera without an AA filter has VERY GOOD base capabilities for getting long DoF's....!
The AA filter is as I've said a very angle-dependent piece of material. Light falling on to the sensor from straight ahead doesn't even notice the AA filter, it isn't blurred at all. Light falling on to the sensor from an angle gets blurred, and MORE blurred the more you increase the angle (and hence the better corner- and F1.4-performance of cameras without AA filters). Both corners and large apertures mean the same thing - increased incoming light angles.
This means that spherical aberrations (undercorrected, soft-bokeh-lenses) get amplified as well, and this shortens the DoF by a quite noticeable amount if you have an AA filter. This is one of the things that can be labeled "digitally corrected" about new lenses, they optimize the lens differently.
So, if you KNOW that you're going to shoot a lot at F11, if you KNOW that you're going to do a lot of product / close range shots with DoF requirements being without an AA filter is all positive. Your shots will be sharper, you will have no visible moire/aliasing AND as a bonus you get a deeper DoF than a filtered camera would give you in the same situation. All good.
My problem is that more than 50% of all my shots are at medium distance, with very good lenses at F2.8-F5.6, in good light. Smack in the middle of "uh-oh... here comes trouble..." range.
Kit Laughlin wrote:
@ theSuede: what are your recommendations re. good programs for sharpening (I too use Aperture [and C1Pro], but have been playing with RPP, as well? Thanks for your contributions here, too.
As long as you know your way around the limitations of the program, PS still rules for overall flexibility. I don't know of ANY other program that allows for "real-world scenario" sharpening.
I'll try to explain very briefly.
What you REALLY want to sharpen is the image as the sensor captured it. As the lens conveyed the light. After all, this is where most of the "sharpening need" exists - barring for "output sharpening" which is a visual / artistical choice - it has nothing to do with compensating for lens blurryness.
Basically, to get optimal results you want to sharpen the image as it is in the first stage after the de-mosaic stage - before you start mucking about with color corrections, added contrast curves and gamma-corrected RGB color spaces. You want to work on linear, non-processed "as it was captured" data if you want to compensate for lens blur.
Unfortunately this is NEVER the case in commercial software, what you get is that the image is distorted (tonemapped, curved and so on) and really "pre-baked" before it actually arrives at sharpening. This means that you sharpen on something that is non-linear - your sharpening will effect bright- mid- and dark regions differently. It will also effect color differences in a weird way, and generally muck about with everything.
You WILL have oversharpened dark-on bright details long before your sharpening will do even close to anything useful for "surface structure" in bright regions. This is what in my opinion gives the "plastic look" that many find to be a lot worse with AA-filtered systems (and it IS worse... if you follow all the "normal" processing flows!).
Noise reduction makes this even worse, as it tries to keep high-contrast edges and smooth low-contrast regions.
All detail needs to be sharpened by the same amount, no matter if it's bright-on-dark, dark-on-bright, surface structure (low contrast) in bright regions or in dark regions. Anything else than this will give a slightly "processed", unbalanced or unnatural look. And unfortunately the normal workflows makes this happen almost every time.