What is X3 Fill Light doing in SPP?

[Tonygamble]

I'm going to experiment using SPP to process unaltered RAWs to Tif and doing my post processing with either Picture Window Pro or Qimage (No, I don't use/like LR).

Before I do I wonder if someone can explain what the X3 Fill Light slider does? I ask as it is not like the usual fill that lifts shadows without losing the true blacks. As it lifts the shadows it seems to often pull back more info into the highlights - noticeably with puffy clouds in a blue sky.

Maybe it is an inverted contrast 's curve'. But I am guessing.

Does anyone have a suggestion?

Thanks for all info that might come.

Tony

 

[Tonygamble]

Maybe I can give this thread a jog by pointing you to :-

portfoilo_2 Photo Gallery by mike earussi at pbase.com

I understand the first nine shots were created by using negative X3 Fill.

In the m43 forum of por getdpi they run a thread dedicated to bokeh. I wonder what they'd think of these?

I know what I am going to do tomorrow. Forget about moving from SPP and spend some time experimenting with the Fill.

Oh, by the way, the lead came from a similar thread I started with the Sigma owners on DPR if anyone is interested.

Tony

 

[shakeshuck]

I don't know what it's doing on a technical level, but I tend to use it when there's too much dynamic range in a shot - change SPP to underexpose overall then pull back what you can with the fill. Works well for some HDR situations.

I'm still undecided as to what to use for post. I don't like the way most (all?) processors won't do in-built lens corrections on Sigma files (when saved as tif). It must be the way Sigma writes the lens data into the exif; usually the focal length the shot was taken at is displayed, but not the actual lens used.