Re: convince me exposure fusion, blending, any sort of stacking is way different than HDR
curious80 wrote: gdanmitchell wrote:
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... In their more extreme manifestations, I believe the exposure blending comes closer to presenting the subject in a way that is similar to how our visual system works. We tend to compensate without knowing it as our eyes scan around a scene, adapting to overall low light in one area of our field of view and then adapting to overall brighter light in another. Roughly speaking, this is what exposure blending tries to do - it produces an optimal level of luminosity in an area of the image, whereas (to be a bit crude about it) HDR tries to maximize the dynamic range in every part of the scene.
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Thats an interest way to look at it. But doesn\'t that mean that you mainly need better manual control over the tone mapping process to be able to get the desired output from HDR.The HDR image (before tone mapping) has all the information about the scene that is needed and theoretically given an appropriate tone mapping it can produce the same output as exposure blending.
Not quite. A lot of the work for exposure blending is quite subjective, and involves some subtle decisions based on what you observe about the effect on the photograph as you work on it. For example, in my example above, in some places the blend between two images might be relatively abrupt while in others it might be much more feathered. And my decisions are not simply made on the basis of technical elements of the image - the luminosity are area A and the luminosity of area B - but of my personal knowledge of the original scene and what looks believable in that context.
Software lets us automate some things about post-processing in very useful ways. However, it is far from being able to make the best personal judgments about what best reflects the vision of a photographic artist, much less being able to actually have such a vision. I like to say that \"a great photograph tells us more about the photographer than about the subject.\" When the software starts making creative decisions, the photograph tells us... about the software?
By the way, sophisticated use of what is normally called \"exposure blending\" (\"fusion,\" in this context, is a new one for me) involves much more than simply selecting which of the component exposures has the best values for a large area of the image. It can start that way, but there is a lot more you can do.
Here is one example. Imagine a shadow area of the image. While you might simply use the brighter exposure of that whole area, you might also discover that this looks unnatural. So, you may modify the process in some or all of the following or even in other ways:
1. You might keep the overall darker image and create custom masks to allow only \"spots\" of the brighter image to apear.
2. You might do the opposite: work from the brighter image and partially darken them by introducing some percentage of the darker version by painting or otherwise creating a mask.
3. You might well apply independent luminosity curves to each of the exposure layers to optimize their contribution to the overall image.
4. In some cases you may even color balance the layers differently, for example in cases where the dark area has bluish shadow light and the dark areas have warmer light.
5. You can \"spot blend\" to deal with very small and very bright highlights - say a reflection of direct light on a granite rock or the surface of water.
Dan
Dan
Nov 20, 2011 at 01:39 AM
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