What is HDR?

[Shudderbug]

What is HDR exactly? I've seen the results and it's something I would like to do but is it something you do on the computer when editing the picture or is it just a result of a combination of settings that you set when taking the picture? Any help would be great!


CC

[JimmyG]

From my limited understanding, HDR is the effect of merging multiple separate exposures of the same scene into one file. A camera can only capture so much light range of a picture at one time i.e. there will always be parts that are not exposed properly in very contrasty shots (such as taking a picture out a window from inside a room). HDR lets you capture all the high and low exposure zones of a shot so that you get a more realistic view of all the highlights, shadows and tones for that image.

I don't have a lot of experience with it, my HDR shots don't come out very different than a regular shot. It's a learned technique.

[Gibbo]

click here (http://en.wikipedia.org/wiki/High_dynamic_range_imaging)

[Shudderbug]

Sorry, I should have said that to begin with. I know roughly what it is, I actually did check that link, but I was wondering how you make an HDR image approximately. 'Cause right now I have no clue how to start taking one.

[Gibbo]

oh right, well.. i remember watching this video when i first tried out HDR.

It will probably help a little more than me rambling on about how to do them:

HDR Video (http://www.youtube.com/watch?v=kRPBX3IbXq4)

[bjordan]

To get my feet wet, I downloaded Picturenaut, did AEB from a tripod: -2 -- 0 -- +2 and loaded them up. Then, you go to tone mapping and make it look the way you want it before saving and tweaking the result.

[Shudderbug]

So you combine the pictures? BTW, thanks, that's a been very helpful.

[Mike]

Yes, you combine the shots. For example, I used 5 shots (Ithink) for this HDR image:

http://farm4.static.flickr.com/3641/3580089678_92f77574c6_o.jpg

To shoot it, I placed the camera on a tripod, set the camera at ISO 100, Raw and M, selected my aperture and then used the exposure needle as a guide for my shots. I then took 5 frames at -2, -1, +/-0, +1, +2 exposure values. I used software called Photomatix to combine the shots from the RAW files.
HDR is not something that can be done in-camera alone, software is always needed to achieve the result you want.

[bjordan]

So you combine the pictures? BTW, thanks, that's a been very helpful.

Yw :-) Yes, you load the multiple pictures in the software (I used the free Picturenaut) and it combines them into a single image which includes more stops of dynamic range (two up, two down in my example above).

It will look awful because the screen can't display all that dynamic range. So, the second step is "tone-mapping" to squish all of it into something we can see.

It does some other things too, like attempting to align the pictures if they're off a bit.

[Spacemunkie]

Have a look at Photomatix or the PS plugin that they make. A decent app for creating HDR. Here's a couple I did yesterday from only 2-3 exposures each (with a bit of PS on top):

http://farm4.static.flickr.com/3299/3666644371_142756f941_o.jpg

http://farm4.static.flickr.com/3331/3666009649_d0463b321c_o.jpg

You see all sorts of horrendous use of HDR and this gets it some bad press. It's just a tool. Trick is to decide what you want to do with it and not let the effect dictate your end product too much. I often use tonemapping for specific parts of an image and then layer mask them back into a single exposure. I always work the tonemapped HDR as there is usually some clean up work to be done - noise reduction, sharpening, colour tweaks, cloning etc.

Edit: Shoot at as low an ISO as you possibly can. HDR magnifies any noise in your images massively. Use a tripod too :)