Friday, December 17, 2010

Those High Dynamics

January’s competition will ‘force the issue’ of High Dynamic Range or HDR. You can resist all you care, but the forces of technology and digital manipulation are poised to wear us down to their will……..I suppose I shouldn’t be so dramatic, but I couldn’t resist!

High Dynamic Range is the capture, and merging of two or more images for the purpose of portraying scenes as it appeared to the eye at the time of capture. At least that’s the way I’m telling it, and I’m writing the blog!!

This doesn’t have to be especially difficult. It is possible to take advantage of “layering” images and ‘erasing’ portions of upper layers to expose portions below that have the correct tone and exposure at one extreme of the visible range while leaving portions of the upper layers that have the correct exposure for mid tones and the ’other’ extreme of the visible range.

That can be a tedious, but effective way to achieve HDR. Luckily, there are millions of people with not much else to do but write software. Watch out! There everywhere you turn! Some of them have an interest in digital imagery, and have resolved the tedium of layering and erasing to achieve HDR. Bless them. Now, if they’d stop writing ’apps’ for the dopes too thoroughly preoccupied with their Iphones!

Adobe Photoshop CS$$$ and Corel Paintshop Pro have HDR functionality built in. Photoshop is quite expensive. Paintshop Pro is much less expensive, and their HDR functionality is not overly well developed. There are options.

Picturenaut is a freeware (or ‘donation ware’) package that’s been favorably reviewed. Jump onto the link below and look over the developers presentation.

Another product is FDR Tools ( FDR is not as robust as Picturenaut. It also happens to be the one I bothered to download and use. Since I move slowly is the Ethernet World I’ve not bothered to test Picturenaut. So, what I’m about to demonstrate is what you can do with number two….I mean the second best of the freeware stuff, not the other ‘number two’.

The first thing you need is two or more images of the same subject. One image should be exposed to capture shadow detail and the other highlight detail. It’s a good idea to have a third image exposed for the mid tones of the scene.

I have three images from our 2007 Campobello trip. One image was underexposed by one stop (should have been 1.5) to grab the highlights. A second image was overexposed by one stop (should have been 1.5) to get shadow detail. The third was exposed for the mid tones on the boats hull.

My first step is to boot up the FDR software. I’m greeted by three windows. The larger of the three is the one of interest at this point, because here I can tell FDR to fire Harry Truman…..oh, dear! I’ve wandered off again…..

I can click on the Projects menu option and select Create New Project. I then navigate to the folder where my subject images reside, select them and click ‘Open’. FDR does not have a progress bar. So, you do not know if anything is happening for a while, but the software does work behind the scenes.

Much like the kitchen help in my future mansion after Cyndi hits Powerball. That assumes Cyndi won’t toss me into the kitchen to BE among the kitchen help.

After a time three thumbnails appear in a small window. By clicking on the imag
es in this window and clicking Edit, FDR’s kitchen staff toil quietly away. After a time FDR spits out a tone mapped image in the mid sized window to the one we’re working in.
If you click on the Align button, FDR will evaluate each of the three participant frames and adjust them for a best fit.

Once the alignment is done click on the Save button. Once you’ve given the image a name and click OK, a substantial amount of time lapses before the kitchen help gets the ’pie out of the oven’!
You still end up doing some work
(saturation, and sharpening) with image editing software,
but you are done with the HDR effort.

Give one of the freeware/donation ware HDR software packages a shot. The process can be as simple or complicated as you want, but not necessarily expensive!

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