It is a in the human nature to try to push things farther and farther as much as the technology allows. But sometimes it turns that it is not necessary and it does not do any good. My question to you is on what medium will you display this high dynamic range image that you plan to capture? Because no printers or electronic monitors will be able to reproduce that much dynamic range, even if you compress it.
Hi,
Judging from your remarks, there seem to be a few misconceptions about what HDR photography is (or should be) about.
First of all, the scene as captured will often have a range of luminosities that will be compressed for viewing on your display or on print, even if you do nothing special to it. The problem is that as the scene contrast gets higher, the rendering of all tones from dark to light in a limited dynamic range output modality such as a 200:1 display, or even worse a 100:1 (glossy) print, wil result in a very low contrast dull looking output. So some sort of tonemapping is usually required anyway.
Second, when tonemapping the image, some significant local tonal adjustments may (have to) be applied. This typically results in poor shadow quality, assuming the initial exposure was correctly exposed to only just avoid clipping of the highlights. The goal of exposure bracketing is first to achieve the best possible exposure for the highlights (maximum exposure while avoiding unwelcome clipping), and second to increase the quality of those shadows (improve signal to noise ratio).
My experience is that using lots of shots does not come for free. You loose sharpness and gain very little DR.
My experience is different, but it may have to do with your subjects (moving objects are not as suitable for HDR bracketing), or your technique.
Let me illustrate the situation with a few image fragments. The image has no particular artistic merit, it was a demonstration file shot for a client.
Here are 2 different bracketed exposures of the same subject. The first was a little less than 1/3rd of a stop below clipping of the Raw data. The bracket (not shown here) with 1/3rd of a stop more exposure had clipped green channels in the sky area, so might have survived highlight recovery, but I was aiming for a perfect ETTR exposure. The second exposure was 10.67x as long (= +3.42 EV), which is not a problem with stationary subjects, and obviously has significant (unrecoverable) clipping of highlight detail, but also much better shadow detail.
Here are three crops of the relevant shadow area, at 100% zoom, no noise reduction, no sharpening. First one is the correct ETTR highlight exposure version, the second is that same exposure boosted in Raw conversion, and the third is from the longer exposure time version. Mind you, there was no tonemapping applied other than a gamma conversion from linear Raw to sRGB. Additional tonemapping would have exaggerated the shadow issues even more.
When these two are combined in a single file (I would normally use a few more intermediate exposures), it becomes possible to significantly tonemap the local contrast of the images for a more realistic look (as we saw it in real life) without compromising the shadow and highlight detail quality. And this is just one of many possible tonemapping renderings.
And this scene was shot under an overcast sky, imagine what would have happened under direct sunlight ...
The goal of HDR and exposure bracketing is to provide a more robust set of data for further postprocessing. It obviously benefits larger format output more than reduced size web images.
Hope that this helped to explain the issues a bit.
Cheers,
Bart