SD14 "too green" analyzed

It is often said that SD14 foliage or grass is "too green". Some like it, some don't. All three of the SD14s that I've owned were the same - too green. Since the SD14 doesn't have color modes, I speculate that Sigma leaned toward pretty landscapes when deciding the 'Sunlight' WB correction and went a bit too far, IMHO.

Although some have said that the effect is one of excessive saturation, personally I believe it to be more like a hue shift caused by too much gain in the conversion matrix for the middle layer  - so today I looked at that possibility.

First, here's a comparison between Custom WB and Sunlight WB with no color-balancing applied to either:

Like Tom (tagscuderia), I prefer the Custom rendering - no way that my grass and weeds are that green!

In the GIMP, it is possible to decompose an RGB image into three layers - hue, saturation and brightness. Then the hue (only) layer can be extracted and exported as a JPEG. So here are the hue layers for Custom and Sunlight compared. Particularly, please note the Kodak gray card below the chicken:

A word of explanation about hue imaging using color:

All colors are show 100% saturated and max brightness, hence the garish appearance of the image. Colors that are close to gray in the capture are somewhat indeterminate - after all what hue is gray?! That is why the gray card at left is all blotched up which occurs with close to neutral captures.

On the other hand, the solid green in the gray card is telling use that it's hue in the image is a definite green - no matter how saturated which means that even if the card was only a bit green, it is definitely green.

Running the eye between the two hue images there is definite indication of a green cast in Sunlight WB.

Now I remember why I sold my first SD14 which was intended to replace a Nikon D50. Now I realize that Tom is right - use Custom WB as a matter of course, or at least have a neutral object in the scene, eh?