in praise of RawTherapee, "Amaze" demosaicing algorithm

Started Jun 10, 2011 | Discussions thread
OP RussellInCincinnati Veteran Member • Posts: 3,201
another AHD versus Amaze demosaicing comparison

Of interest to some of the more technical forum contributors might be the way that different Raw (or JPEG for that matter) demosaicing algorithms can have a huge effect on a lens's ability to crisply image fine detail.

Here's a 100% crop comparison of the Amaze demosaicing algorithm on top, versus the more typical AHD demosaicing.

The slightly unsettling thing to me is that a few weeks ago, I would have sworn that the top photo was taken with a much sharper lens than the bottom photo. But of course it's simply the same .ARW raw image file, "developed" in two different ways. Both images received, as a final step, the same radius 1 unsharp masking (i.e. a typical kind of sharpening of a photo at its final display size).

Am saying it's unsettling because many of us spend a good deal of time noticing the difference in fine detail rendering among various lenses. But it appears that as you get down to the finest levels of detail, you should not be 100% confident that differences you see in images are really due to the "lens's image quality".

Am not saying that all lenses are the same. And of course if you look at the corners of single image, and compare the clarity with the center of the same image, you can make fair statements about the lens's overall resolution consistency.

But we are on much shakier ground when we try to compare resolution or contrast or color rendering of cameras and/or lenses via sample photos, when the exact post-processing details may also vary across the different images.

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