RAW Converters Comparison (8 compared)

Started Jun 12, 2014 | Discussions thread
bronxbombers4 Senior Member • Posts: 3,387
Re: Raw converter without demosaic choice

bford wrote:

newmikey wrote:

As some have suggested, different demosaicing algorithms perform differently on various subject-matter and/or ISO levels.

Using raw software that lacks an option to preselect any particular type of demosaicing routine seems counter-intuitive to obtaining maximum result out of a raw image. There are just too many trade-offs. As an example,

  • Variable Number of Gradients interpolation computes gradients near the pixel of interest and uses the lower gradients (representing smoother and more similar parts of the image) to make an estimate. It is used in first versions of dcraw, and suffers from color artifacts.
  • Pixel Grouping uses assumptions about natural scenery in making estimates. It has fewer color artifacts on natural images than the Variable Number of Gradients method; it was introduced in dcraw from rel. 8.71 as "Patterned Pixel Grouping".
  • Adaptive homogeneity-directed interpolation selects the direction of interpolation so as to maximize a homogeneity metric, thus typically minimizing color artifacts. It has been implemented in recent versions of dcraw.
  • AMAZE as implemented in f.i. RawTherapee as well as LibRaw to extract every last bit of highlight detail from the raw file. AMaZE works best with low ISO images that are relatively noise free. It is not the best choice for high ISO images.

Also, have a look at this demosaicing comparison

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Once you eliminate sharpening and other editing that may be going on, raw conversion is essentially identical in most apps today, no matter the ISO. I think Raw Therapee's options are more of a matter of providing solutions for a problem that no longer really exists, at least in a meaningful way.

Not at all. What is a thin line ACR may turn into a dotted line in C1. What is a stair-stepped line may be smoother in C1 (so long as it's not so skinny it runs into the dotted line horrible issue). What is color moire in ACR may not be in DPP. What is nasty zippy artifacts in DPP may not be in ACR. etc.

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