Zillah's High Dynamic Range Tutorial

Zillah

Ha, I'm putting my name on all these things, then I'll be famous


Intro:

Right, I'll begin with a brief explantion of what this tutorial is about. HDR photography, in a nutshell, is a method of shooting and processing photos that allows for you to capture a more comprehensive range of light and dark in a single image. The end result is much closer to what the human eye would see than what a normal photo can capture.

Ok, first a bit on how normal photos work and why HDR kicks their asses. When you take a photo you are trying to capture as much detail as possible. However, certain parts of a lot of images are either too bright or too dark to capture all the details.

For example: Imagine you are taking a photo of a friend. You are inside a darkish room, with a bright sunny day outside. Your friend stands at the window.

So, you have two choices with the photo:

1 - You can expose the photo so that it captures all the details of your friend (like his face and clothes) but then the background will be completely blown out because it is far too bright.

2 - The other option is to expose the photo so you capture all the details in the bright background, but that means that your friend will just be a silouhette and have no details on his face or clothes because it is far too dark.

Here's a quick example using my hand and a light:




In the first you can see some details on my hand but the background is blown out, and in the second you can see the details of the wall but the hand is too dark. You can't get around that with normal photography without using a flash, and a flash won't work for a lot of bigger things like buildings or landscapes.

What you need:

1 - Photoshop CS2. You have the have this edition, older editions do not provide HDR.
2 - A tripod. Absolutely essential, if the camera moves at all it won't work.
3 - A still subject.

Step 1 - Shooting

Set up your tripod and camera to capture something. In the example I'll be using I just shot my computer desk. Presumably you'll be using something prettier

Ok, set your camera to manual and do a couple of test exposures (or light readings if you're not using digital). Get a feel for what makes a decent exposure under the current conditions.

Now, take one shot that is too dark. It should be about four or more light-stops darker than you might have normally taken. This shot will expose the details of only the brightest parts of the image, and everything else will be too dark.

Now, being very careful not to move the camera at all, take another shot that is a little bit brighter, perhaps one or two stops more light. Then take another one, a little bit brighter again. In the end you want about five or more images, the first being very dark, the last being very bright, and with one or more in between. This is the selection I took for my example:




Notice that in the brightest image the computer screen and the wall are completely blown out, but we can see details in the rest of the photo. The darkest photo is the opposite, we can see details in the wall and the computer monitor, but the rest is too dark.

What we'll do in step 2 is use photoshop to stich all the images together and it will create one composite image that gives us the best of both worlds.


Step 2 - Processing

Open up photoshop and go here:




Which will lead to this:




Make sure the option "Attempt to automatically align etc" is ticked, thats quite useful for if the camera moved a tiny bit. Now, click "browse" and select the images you shot earlier and click OK.

The PC will have a heart attack for a minute and then will present you with something like this:




Now, see where that arrow is pointing? Does that look familiar? It work the exact same way as the "Levels" option. If you're not familiar with that go take a look at my "Basics" tutorial.

The difference here is that it is asking you how bright the brightest parts will be. Slide it to the right until you can see the details in the brightest part of the photo. For now it will look a little dark, but don't worry about that for now.

Notice also that just above the levels display is a little box called "Bit Depth". It should currently be on 32. This essentially means that the image currently holds more tonal information than your monitor and most printers could possibly do justice to. If you want to export jpgs you'll have to lower it to 8 bits, which is fine for pretty much everything. You might want to keep it at higher bit depth if you're going to be printing some incredibly high quality prints, otherwise just set it to 8.

Once you click OK it will bring you back to photoshop and present you with this:




There's little to do with this, I find that all I need to do is whack the gamma up a chunk and it brings the levels up to a nice balance. This area also has "Highlight Compression". To be honest I'm not sure how it works but it can be useful for some images, it seems to be something of an auto mode. This bit and last are very much trial and error. Experiment until it looks right. Too much gamma and it can look muddy, too little or too much exposure and you ruin the details.

To finish it you might want to try auto-levels and maybe a little bit of sharpening.

Here's the final result from my example:




And here it is compared to the other photos:



Pay close attention to the various parts of light and dark. See how we kept the best of both worlds? The halo around the light is drastically reduced but we can still see all the other bits clearly.

I'll finish this with some examples of the kind of stuff you can get with HDR from Deviantart:

http://www.deviantart.com/deviation/41406276/

http://www.deviantart.com/deviation/39366447/

http://www.deviantart.com/deviation/32753779/

http://www.deviantart.com/deviation/35789708/


I'm still relatively new to this myself so if this was helpful or if you have any suggestions/questions then please post.

Zillah

No love for the HDR then Bunch of philistines!

tab126

I love HDR, though I'm away from my computer that can do it. I'd use a better example for your tutorial, though. Your range/subject is beyond normal ranges, but not by that much. Also, part of the computer monitor is still blown in your final.

I saw a picture recently of the sun behind a tree. I think the only way they could have gotten that was HRD. Just a thought.

sionnach

You're using a very poor image to demonstrate the usefulness of HDR and you've haven't really described the most important part of the process, the tone mapping. You really should know what you're talking about before putting up a tutorial.

Sorry if i've been a bit harsh, just my honest opinion.

Zillah

sionnach wrote:

You're using a very poor image to demonstrate the usefulness of HDR

I agree its not all that good an image, but it demonstrates the principle and I specifically linked to other images that show the kind of thing that can be achieved.

and you've haven't really described the most important part of the process, the tone mapping.

Uh, yes I did, I just didn't call it that or get too technical.

You really should know what you're talking about before putting up a tutorial.

Does the tutorial show someone the basics of how to do a HDR with photoshop or not? Because that was my only intention.

sionnach

Zillah wrote:

Does the tutorial show someone the basics of how to do a HDR with photoshop or not? Because that was my only intention.

It shows how to make a poor HDR, if you're going to make your tone mapped HDRs in photoshop instead of using the superior Photomatix then you at least tone map using local adaptation, not exposure and gamma as you've taught here.

Zillah

Would you care to do your own better tutorial or are you just here to complain?

sionnach

There are already lots of great tutorials out there for HDR, a good basic one for beginners that covers both photoshop and photomatix is here:
http://www.popphoto.com/howto/3038/how-to-create-high-dynamic-range-images.html

A more advanced one for photoshop that goes into far more detail can be found here:
http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm
^^ i'd recommend checking out pretty much all the tutorials on this guy's site, his work is spectacular and his tutorials cover a wide range of techniques for improving your photographs.

Zillah

Hey cool...