Wow! I feel like I just got tutored by some real pros! Thank you all for coming to the rescue. Your answers really helped me better understand this. They did raise some questions that I would like to independently ask. It seems you all noticed you schooled me with the same answer but each way told was different. This was helpful showing me different ways of explaining it in that I see a bigger picture, but I do have a few specifics I wouldn't mind cleared up.
The problem is that the controls in RAW converter are for the most part global to the whole image. Lightroom and ACR do have some localized edits, but they're pretty limited (for instance no fill light or recovery sliders, to use your example). What happens is that if you try to boost the shadows and recover the highlights in a single RAW conversion, you end up with a dull and lifeless image. A pleasing image needs contrast, both local and global...
but LR does
have fill light and recovery sliders...? Perhaps you didn't mean to write "no" and was using fill light & recovery to explain your later explanation that when you adjust one you effect the other--making the image dull and lifeless. This struck me like lighting as I finally realized how such global control would effect the curve. Indeed we want to keep the contrast, and local control makes sense!
This is not always so straighforward. I can adjust the mapping in the raw conversion (fill light, recovery, curves, etc.), but that will effect the entire image. However, that is not working in the example I showed above: parts of the rocky areas are quite dark, and they are supposed to remain so. Lifting the foliage out of the shadows ruins the contrast on the rock surface.
another great explanation... Then I wonder "when creating HDR (or WDR, let's not focus on HDR) how does it know which part of the scene is rock or foliage without complete manual control (ie. masking in photoshop)".. This is partially answered by more great replies I will quote below but I'd like your take on it. Unless it's part of a scene you can easily mask (i.e. the sky) how can you lift foliage that's mixed in with rocks you wish to stay the same? Let me comment on the other replies that discuss this but your specific example seems particularly unique and difficult and I'd like your take on it.
...In many cases, an efficient DR mitigation can be made from one raw exposure in LR/ACR, by the simple use of fill light/blacks (and to the expense of noise in the shadows).
However, if eg extensive highlight recovery is needed with the tone curve (as in the excellent Mark Segal's essay), then you hit the fact that the tone curve is not a "masking" tool (ie it affects all pixels of the image), and you have to rely on masking in PS or other pixel-level editing app (until LR's brush can do tone curve adjustments)....
If shadow noise is not a crucial problem, one exposure at base ISO taken for the highlights often does the trick.
this is where I realized how by masking using 2 differently developed photos really makes sense. And Mark's essay was a perfect example with that blown sky. I completely see how by recovering the sky you would also recover the building and loose contrast there. But this is easy to mask as it's an isolated part of the scene. In other cases the two could be mixed (like Panopeer's).
I know LR can do curve adjustments, what do you mean by LR's brush
do tone curve adjustments? Also I'm having trouble understanding your last sentence. "...one exposure at base ISA.." Do you mean process the RAW file bringing down exposure for the sky? and how would that effect shadows? or do you mean simply take the photo originally at base ISO unless you're worried about bringing up the shadows? Could you please explain that? (I didn't think you're talking about blending an HDR because we're talking about one exposure)
To say it a fourth time, but different:
a pixel with for instance 50/50/50% R/G/B somewhere in the shadow area needs to move in a different direction (eg lighter) than another 50/50/50% pixel in the lighter area (eg. needs to become darker). A raw converter cannot do both in one pass since it only changes similar toned pixels in the same direction globally.
Great explanation also. But having two similarly shaded/colored pixels in two other regions would require the editor to know the difference between them.. Answered below but brings other questions.
That's a good description of the problem! However... keep in mind that some tools in some raw converters already do that based on the surroundings pixels : eg, Fill Light will probably lighten it if there are only darker pixels around, not if there are only lighter pixels.
There are already mask-based tools. The problem is when you hit their limit!
I did not realize this! How can I find out which program does this and what the limit is. Essentially this could mean processing one version would be enough so long as these limits work for the image. What are some mask-based tools I could learn about!
It's a question of which software tool or method is more adequate to ease the task. The information contained in the RAW file (or files) is the same for all of them:
- A RAW developer with shadows/highlight and so forth sliders and options
- Two (or more versions) of the same RAW developed at different exposure values and manually blended in PS layers
- A specific tone mapping tool designed to enhance local contrast while reducing global contrast like Photomatix
Using 2 (or more) versions of the same RAW file developed at different exposures allows to easily obtain the desired result, and meanwhile there is no other clear winner option this will be one of the methods to use....
If not even a specialized HDR blending software manages to achieve better results than a proper PS blending, why should we forget manual solutions and think a software tool should always be preferred?
Great examples, thank you for sharing! In fact after posting yesterday I spent more time better understanding Photomatix and learning that in generating HDR the choices in processing yield far different results. Naively I thought HDR was one thing, as if a tool to be used globally. Now I'm really seeing the bigger picture. How in Photomatix you can go the tone compressor route or the details enhancer route. But how you can also simply go the exposure blending route....and then the manual masking route like in Mark's essay. I'd like to learn your method and will look at that tutorial. Bottom line, it depends on how you want it to look.
If I've learned correctly, the tone mapping software route like Photomatix would be good in global situations where you want enhanced DR without flattening out the curve...!! ding, ding, ding---is that correct!? But in other situations where global adjustments are unwanted this may not be the correct route. In those cases it seems manual blending (via masking) may be best.. Under what situations have you learned each method should be used?
My tutorial on this very topic was published on this site yesterday. It's not HDR but it works. How and to what extent would vary from image to image.
...and what an excellent essay it was! Thank you so much for your tutorial!
I know this reply is long but I can't be more happy with any thread I've ever started! This has really helped me a lot. I really look forward to hearing back from my last questions! Then I really think I'll have a well rounded understanding! (This is now my preferred forum!)