On the dynamic range of RAW...

Started Nov 30, 2004 | Discussions thread
Alexey Contributing Member • Posts: 755
Re: Blending

Brian G. wrote:
Hi Alexy,

Alexey wrote:

Why use blending in this situation if PS shadow/highlight is
available? Or does blending provide some advantage?

Yes, blending exposures does provide advantages overr
shadow/highlights. The most important is that you cannot recover
lost shadow or highlight detail this way. By this I mean that if
the value had gone to pure black or pure white, there is nothing
that shadow/highlights in PS can do. But often, the information is
still there in the higher-bit RAW file. So we can bascially
extract the best from both the shadows and the highlights and put
them together. Also- although pushing the RAW exposure up to
recover shadow detail can increase visible noise, the shadow slider
in PS will increase noise more.

Actually, I meant using shadow/highlight slider on the 12/16 bit flle, right after converting it from Raw (with Photoshop Raw conversion tool). The information should still be there, I assume. As for the noise increase, you may well be right, but I do not understand why Photoshop raw converter would not increase noise, but Photoshop with 12 bit file would?

In the layer mask mode, what does Gaussian blur do and how do you
determine proper values? It that what you would have tweaked to
make blending perfect?

Anders is correct- it's used to make the blending transitions more
transparent/smooth. Proper values, for me anyway, are determined
empirically. And it definitely could have used some tweaking in
the example I presented here.

What do you mean "emperically?" As far as I understand it, the greater the value, the greater the penumbras around the subjects are and the smaller the number, the rougher/more contrasty the transition looks. Or is it the other way around?

Again, thanks for wonderful presentation.

Thank you, Alexy. I am happy you found it informative.

It's just very inspiring to see someone devote such time and effort to selflessly give something to others. Again, thanks.

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