[HDR-photo] Real-World example (Was: Alignment)

[Bernhard Vogl]

Hello Pablo,

> If its a global mapping this should not be a problem, since it just
> corresponds to modifying the response curve. If it depends on the scene 
> or uses some kind
> of local tone mapping (which is much more computationally expensive), 
> then the mode is not suitable for the creation of scene referred HDR
> images.

I think, it's a "global operator". In-camera CPUs are not very fast and a "local operator" is computationally much too expensive.
Is is quite noticeable, how the camera slows down when switching to extended mode... ;-)

> If the curves are static and do not change between the images, it should
> be possible to recover it, no matter if they are more S-shaped or not.
> The resulting HDR image will probably show considerable quantisation
> effects due to the shallow ends of the shaped curve though.

It is far beyond my knowledge how Photomatix and other software products compute the camera response curve and why this shifts exposure. It's just what i encountered with my "real world examples"  :-)
The quantisation artefacts, by the way, are noticeable in the discussed example...

Best regards
Bernhard