What exactly is HDR?

Candid Arts

I understand that it stands for High Dynamic Range. But I have no idea what that means. How to you use, when to use it, why you'd use it... Etc...

Can you use it in CS3? Is it a plug-in? I've been reading a few other posts about it, layers mask merge, photomatix. I have no idea what any of this is. I'm pretty new to Photoshop and post processing, so I'm not sure on all the terminology within. I can use my camera pretty well, LOVE the techy numbers stuff, but yeah. Anyways...Some help would be much appreciated. I've loved the examples shown on the forum lately, the colors and saturation look beautiful. I tend to do more natural un-processed photos, but would like some extra saturation and more intense colors in some cases.

Thanks everyone.

jfriend

http://en.wikipedia.org/wiki/High_dynamic_range_imaging

Photoshop can do it and there are several relatively new programs like Photomatrix that have specialized in doing it.

Candid Arts

Interesting. So photomatrix is a program for doing HDR composites?

So how do I do an HDR? Do I just put three differently exposed photos (-, 0, +) into a stack and the HDR program automatically selects the highest dynamic ranges of each photo and layers them together to form the new image?

BinaryFx

Candid, there appear to be two separate approaches to HDR.

1. Exposure blending/fusion/merging direct to a 16 bpc or 8 bpc "rendered" file.
2. Exposure blending into a linear 32 bpc file and then tone mapping down to a regular 16/8 bpc rendered file.

I prefer option 1, as it often produces more realistic results and does not introduce crazy halos as can happen with less skillful application of tone mapping. The software simply combines the "best" data from each exposure and creates the new image. Option 1 can be done manually, however there are many excellent applications to blend exposures that will save a lot of time. These "simpler" HDR applications do not use tone mapping, just blending.

Option 2 is what seems to be the more common approach used in the big name HDR applications, there are many poor examples of tone mapping to be found with this approach. With skill or perhaps lesser "enthusiasm" one may be able to avoid such tone mapping mistakes. One may also be able to simply blend the exposures without using a tone mapping operator in these more full featured applications.


Stephen Marsh

http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/