Hello there!
I'd like to write a small and naive guide to HDR.
I will be using Photoshop CS5 and my Canon 500D. Still I think you can easily adapt everything here to your camera and to different programs/versions.
I know I'm not a pro at all, but I've been studing this interesting tecnique and I'd like to share it with those of you who still don't know it.
Feel free (and forced) to comment this guide and add everything you want!
What does HDR stand for?High Dynamic Range.
What is it used for?You might often find yourself in a situation where you have to shoot a subject with very dark and very bright areas.
Or, you would like to extend the DoF in your picture, and you can't obtain the result even with high aperture values.
HDR comes in handy, allowing you to merge different pictures into a single one by keeping the most important areas of each single shot.
In this way you can get a picture with a much deeper field, or with a much better light.
What you need is basically a certain number of pictures of your subject, typically three, and merge them with Photoshop's dedicated function.
In this example I will use HDR to merge three pictures with different lights. I still have to try HDR to extend the DoF, so I will leave this to you as an exercise
show me your results and let's have this topic grow.
To use HDR properly, I warmly suggest to use a tripod. You can try to take your pictures by hand, but too much shaking might mess the job.
Still it can be done manually
if you're in an emergency, since PS tries to align the pictures and cut the borders.
So what I did here was putting my camera on a tripod and make sure it was very well stabled.
To take the three pictures I used the AEB function. I will show you how to use it on the Canon camera, I think you can do the same with different brands, just check your manuals.
So what is AEB?It stands for Automatic Exposure Bracketing.
It allows you to take three pictures in a row, changin the exposure time in each photo sequentially. In this way you can later chose which one you like the most and reduce the chance of a badly exposed picture.
All you have to do is set up your AEB, and press your trigger three times. Or you can do that even better using the self-timer function.
Here is what you usually do on a Canon camera.
Set up your AEB by going to the EV menu. Once the EV menu is selected click it and change the value with your roller. You will see two small pointers going far from a central one. They will go further the more you roll.
You can usually set it up from +/-0.5 to +/- 2. In the following pictures I will be taking 3 pictures separated by +/-1 EV from the central picture.
Here is what you get:
Once this is done,
set up your camera to 2 or 10 seconds self-timer.
Now do your usual business and set up an average exposure time and /f. You will have to concentrate on the big central pointer in your EV-meter. The two small pointers will tell you where the 2nd and 3rd picture will be taken.
Once you're ready, press the trigger, wait a while and listen to your camera taking the three pictures. If you listen carefully you will hear three different shutter times, usually the last picture is the longest exposed.
Ok, you're doing fine.
Now let your Photoshop run.
all you have to do is go to File
Automate
Merge to HDR Pro...
Once you're here, press the [Browse...] button, go to the directory where you've saved your pictures, select them and press [OK].
You can try to let Photoshop align your pictures by selecting [Attempt to Automatically Align...]. You might get different result with this option on or off, just do a couple of tests.
Good, you're ready. Press [OK] once again and watch PS do its job. It will take a while, don't worry.
Once the job is done, you will be taken to a new window with different options. Here you can fix contrast, saturation and a lot of other things. There's also a bunch of presets you can choose from top-right. I usually go for "photorealistic".
Do a few tests here too and get used to them.
When you're satisfied with your settings press [OK] and enjoy the result.
You can fix your merged picture with the usual Photoshop's tool.
Here are the three pictures I used in this example and what I got at the end. The result of the process is straight from PS, untouched.
-1 EV:
+1 EV:
0 EV:
HDR merge:
Thanks a lot for ready 'till this sentence
Feel free to comment, suggest and add everything you want!
Oh and don't forget to post your tests!! - Alan
This post was edited by AlPi on Aug 12 2010 09:55am