What is HDR?

I keep seeing mention of "HDR" in the forums...can someone explain what that is? Sounds like some kind of filter perhaps?

I think it stands for High-Density Render. Basically the idea is to merge several frames from varying exposures to capture all of the detail that the film/sensor can't capture in a single frame. Personally I do little of this and would rather use my graduated ND filters but on occasion I've had to.

Thanks Richard. I see the light.

The nice thing however with a HDR is when you don't have a good line for a graduated ND filter. Like a tree covered trail that opens up into a meadow. You can get the shadows and the meadow both to look like you see it with your eye and in a situation that a graduated ND wouldn't work.

I found this explanation on someone's website...is this correct?

"The latest version of Photoshop allows you work in High Dynamic Range (HDR) in which multiple exposures of the same image are combined to create a 32 bit file. When compressing it back to 8 bits, you can really bring out details in the shadows and highlights."

Debbie,

You got it. HDR lets you merge multiple shots of the same scene but you vary the exposure time for each shot. The images are merged to create one with a dynamic range, which sometimes exceeds what humans, printers or displays can reproduce. Adobe recommends two exposure-time value settings between shots, 1/100, 1/250, 1/500, etc.

Thanks Reno. Curiosity is getting the better of me. I think I'll try it next time I'm out.