lone_dingo wrote:
> This is the critical bit... Headroom in RAW. It isn't the same as correct exposure. When you lift the shadows you are effectively increasing ISO. When you pull the highs you are lowering it. As you blend these two images with different ISO settings, you will discover a mismatch in noise and detail that can often be concealed but never overcome. What is happening in LR when you 'balance out' the lights and darks is a blending of ISO speeds as you manipulate different areas of the image.
>
But if you process a single image using LR for different exposure levels and then combining them aren't you doing this exact same "blending of ISO speeds" as you say you would do in Lightroom when you life the shadows and pull the highs? (ie. isn't manipulating the exposure, recovery, fill light, and blacks sliders performing the same processing operations as when you process a single image into different exposures and then combine them? In fact wouldn't that combining process be less exact (unless masking) because the properly exposed blended image would be combined with the less favorably exposed portions in the other blended images.

I did what you said and tested the technique of processing 3 images from one RAW file. For what it's worth I read on luminous landscapes this method of creating HDR-whether you want to call it that or not- from a single image is best only creating 2 images, one for shadows and one for highlights. Regardless I've never done this before and I made 3. My technique will demonstrate that I don't know how to do this. I want to walk you through what I did step by step.

My scene is in Central Park. The underside of the trees are terrible dark. The sky is very bright. I took the most balanced photo of these conditions and made a CR2 file with my 5DmarkII. Using Photoshop CS4 ACR here was my procedure and questions:
#I opened the photo. It defaults to 8-bit. I changed it to 16-bit. Should I have done this?
#Creating the version for shadows; I raised my exposure +1.00. Not knowing if I should only use the exposure slider or not I went ahead and reduced the Blacks from 5 to 2 and raised the Fill Light from 0 to 5. Am I only supposed to adjust the exposure slider?--because it would require a significantly higher adjustment if I were not to touch Blacks of Fill.
#Creating the version for Mids; I thought I shouldn't touch the exposure slider considering it was supposed to already be correctly exposed for the mid average of my shot. To open up the histogram a little and expose better for mids I raised my Fill light from 0 to 42 (pretty significant but what else am I supposed to do?)
#Creating the version for Highs; I reduced the exposure slider to -1.00 and increased the recovery from 0 to 26.
#I then saved all three photos.
#Next I imported them into Photomatrix and had an interesting warning saying: "Exposure informatin is missing, or one or more images have the same exposure settings. Please check the estimated Exposure Values on the right column, if they are incorrect....specify the EV spacing or change the EV manually" The EV values in the right column were interesting estimates it seems. It shows the one created for shadows and mids to have an EV of 0, but the one for highlights is -3?!?! I do not know what I was supposed to do to have this done properly. I just hit okay without changing the values (I'm sure that was wrong)
#I generated the HDR image in Photomatrix and tone mapped. I'm leaving the default settings: strength at 70, black clip is 0, white clip is 0.25. I saved as a jpg realizing later I should have saved as TFF because I still needed to reduce the size in Photoshop down to 20%. I resaved as jpg and the result is below: http://i68.photobucket.com/albums/i17/notastepizzaface/RESIZEhighAnd2more_tonemapped.jpg

Now I want to see how it would compare to simply adjusting levels in Photoshop (or Lightroom) without creating separate exposures to combine later. I took the evenly exposed image and brought it into ACR. Changed the default to 16-bit. I went and used the auto setting since it did a god job. The only thing that was adjusted was Recovery +51, Black down to 3 from 5, and brightness +23. I brought into Photoshop, resized down 20%, converted to 8-bit and saved. Here it is: http://i68.photobucket.com/albums/i17/notastepizzaface/photoshopone.jpg

*What I want to know is how come the DR is better improved in the first method!* I don't understand if you're using photoshop or LR to create different exposures, how come the resulting HDR blend looks different than simply working on the one exposure in Photoshop or LR. That is after all where you created it to begin with.. What is different?! I know something is, I see it! But why!?

Using Photomatrix you can also do this using just one RAW file without having to process it into additional images. This time I saved as 16-bit Tiff and opened in Photoshop, resized down to 20%, converted to 8-bit and saved. The result is below: http://i68.photobucket.com/albums/i17/notastepizzaface/RESIZE20090714-IMG_1794_tonemapped.jpg

Also I want to show you my results from 3 SEPERATE BRACKETED exposures taken on location. I don't remember the bracketed settings but shutter speed is 1/5000, 1/1250, & 1/320 so I guess that would -2EV, 0EV, +2EV. Is there another way to check this?

I created this image in Photomatrix. It looks the cleanest but also a little fake. I decreased the strength from 70 down to 50. I also lowered the gamma a bit and raised the black clipping level in attempt to make it appear more realistic. From Photomatrix I saved as jpg but then had to reduce to 20% size in Photoshop also. Here is the result:
http://i68.photobucket.com/albums/i17/notastepizzaface/RESIZEcentralparktest.jpg

I would *LOVE* to hear any feedback about my techniques, what I did incorrectly, or anything else....