Sandman wrote:
Here's an example of a feature I'm missing in Lightroom.

I use curves extensively, it's the holy grail of exposure editing. If
you're not using it, start using it!

A curves tool does not edit exposure, it changes the
tone mapping. You are only moving points between the
maximum white and the maximum black in relation to each
other.

What you want to adjust, for the purposes stated, are
brightness and contrast. A 'contrast' adjustment changes
the data's range of darkness and brightness. A
'brightness' adjustment moves the range toward one end
or the other of the scale. A curves tool doesn't move
the range nor does it compress or expand it. Curves
moves a portion of the range in one direction or the
other, but cannot go past either end. Areas within the
range are compress and expanded, but not the range.

When done with a RAW converter brightness and contrast
adjustments can be dramatic in effect. If you try it in
an editor with the RGB image produced by the converter
the effect will be significantly reduced, and in
particular if the image has been formatted and saved as
a JPEG.

So here it is in Apertu

http://sandman.net/files/aperture_curves.png

On a slightly (deliberately) overexposed image from Gotland. See the
"Range:" popup? It can be set to "extended", and it looks like this:

http://sandman.net/files/aperture_extended.png

It shows a larger spectrum of image data than can be displayed on your
monitor, i.e. a higher dynamic range. This is only populated if you're
shooting with RAW files of course. You then have more bits of image data
than JPG or your display can show. Using this, I can move the qhite point
*up*:

It is shot directly into the sun! There is no way to
avoid some areas of clipped whites.

When processing the RAW image you can use brightness and
contrast to set the points in the raw sensor data that
become absolute white (255) and absolute black (0) in
the RGB image (whether that is saved as a JPEG or
something else). When editing the RGB image you will
never have access to whatever the raw sensor had that
was whiter or blacker. It's gone at that point.

Other formats will have greater dynamic range than a
JPEG, and at least some of the shadows can be pulled up.

Anyone knows if I've missed something?

A bare bones realization of what each program is doing.
And a misconception of what a curves tool does.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)