Do you use typically use a standard setting in InFocus, or do you adjust the sliders substantially every time to suit the particular image? If you typically use a standard setting, do you mind sharing what it is? I have practically no experience with InFocus, and your observation piqued my interest. However I'm struggling to get it to produce output comparable to Piccure+. It doesn't help that there are 6 values and 1 setting to manipulate! Piccure+ is simpler in this respect.
Hi Damon,
I'll try and be
relatively brief, in order not to get too much off-topic. Infocus is a tool that addresses sharpening of blurred image content, although since it's in its first version (sofar) there are some things that could be improved.
Infocus first addresses what we could call Capture sharpening with the controls of its Deblur panel. This will only allow to restore detail from image content that got blurred during Capture. If one attempts to do more (Creative sharpening of certain feature sizes), then artifacts will quickly start spoiling the result. It allows to address several different types of blur, Generic / Out-of-Focus / Straight motion / Unknown, each having a specific type of Point-Spread- Function (PSF) to be used in reversing the effect. Generic and Unknown are the common types to use on normal images that have some optical blur, and all images have at least that.
The Blur radius setting is the most important,
it should not be set too high. I would rather err on the safe side than introduce artifacts that are much harder to deal with in further post-processing steps. Important to understand is that optimal values for well focused images with good lenses in the Generic setting, will vary with the aperture value used. I typically encounter values between 0.6 to 0.9 for my high quality lenses when used at moderate Aperture values on my camera which has an Optical Low-pass Filter. Cameras without an OLPF tend to produce aliasing artifacts that hinder proper Capture sharpening, so relatively low values (0.5-0.7) may need to be used in that case. The Unknown/Estimate method does well when used on a region of well focused detail, and a radius of more than 1 or 2 is rarely needed.
The use of very narrow apertures (the definition of 'narrow' depends a bit on sensel pitch), will justify using somewhat larger radius values.
Since Infocus uses a relatively aggressive type of deconvolution algorithm, the 'Edge-softness' and 'Suppress Artifacts' sliders will have to be used to taste, in order to avoid ringing, stairstepping, and halo artifacts.
Now, after the inherent sharpness has been restored with the Deblur panel settings, we can add a bit of more traditional (acutance) sharpening with the Sharpen panel. Since the Deblur operation reduced the radius of residual blur, it's common to use a small(er) radius here, unless one wishes to enhance some larger detail sizes. The Micro-contrast control adjusts the local contrast of the smallest detail, which can counteract the effects of veiling glare, and boost the overall impression of sharpness.
Since the current version of Infocus has no controls for addressing sharpness fall-off towards the corners of the image, one could produce two versions of the same image (assuming well focused image content), one sharpened for the center, and one sharpened for the corners, and blend them with a radial gradient mask in e.g. Photoshop.
Infocus requires a lot of tweaking
for the optimal results, although user made generic presets can help to get the proper basic settings to something generically usable. One could for instance make defaults for various aperture settings, to counteract different levels of diffraction blur, or images that are downsampled (with a certain algorithm) for web-publishing.
Piccure+ on the other hand attempts to analyze the image content and automatically determine the optimal type of PSF to use (optionally helped by user input about where to sample in the image), and one just has to adjust the strength of the correction. Noise is not helpful, neither for the analysis, nor for the restoration, although its Noise suppression control does help.
Cheers,
Bart
