Monday, April 17, 2006

My New Hobby

Update: A friend of mine with Photoshop made a photoshop version of the images. See below.

I'm in trouble now. A few days ago I saw some pictures that someone had taken of Tokyo. Ordinarily this would not be a big deal, but the pictures were very surreal and full of detail. This was my first introduction to High Dynamic Range (HDR) Imaging.

The basic idea is that you take a series of photos of the same subject at several different exposures. These photos are then magically layered together to create an HDR image. A tone map is then applied to create an image that you can use on the web or print, etc.

After doing all of this, you end up with an image that is very detailed at all levels, plus the process of tone mapping tends to saturate the colors so that you can get a fairly surreal effect.

The easiest way to do this is by using the latest version of PhotoShop, but I do not have $800 to spend, so I looked around a bit and found a program called Photomatix. $100 is a little more bearable, plus there is a free trial to try out before you buy. I also found a set of programs called pfstools. They are free but a little more difficult to use.

So for my first experiment, I took 6 photos of my house a few nights ago. The only light available was the full moon, and the light coming out of the windows. The purpose of this experiment was to try out the different tools, so not a whole lot of thought was put in to image composition, or anything like that.


This is the image of the house as shot by the camera using all of the default settings, and using its suggested exposure. Note that most of the detail comes from the light coming out of the windows. Othewise, it is difficult to see much detail
anywhere else.


This is the result of using Photomatix. In this photo you can see a lot more detail including the cars, the texture of the masonry around the house, and the trees are fairly detailed. It also has a bit of a surreal look to it, especially when you look at the clouds in they sky, and the edges of the roof lines.


These two images were generated with pfstools. The first was created with the drago03 tone mapping technique. It is similar in ways to the Photomatix image, but not quite a surreal and the trees don't seem to be as detailed.

The second image was created with the rein04 tone mapping technique. It is much darker than the others, though it seems to create a more accurate looking image of what I saw when taking the photos. It still shows a lot of detail where the original photo didn't have enough exposure time to show.


A friend of mine was nice enough to generate a photoshop version of the image. It does a very nice job, and though it seemed to have a similar artifact issue as the others, it chose to use white instead of black and thus is not as noticeable.

If you look close enough you may be able to find some small "artifacts" in the images where the processing didn't work quite right. They seem to show up where the light is the most intense, and thus leads me to believe that I should have began taking photos at a step or two lower exposure as those areas were still overly exposed in all of my photos.

Overall I think my first experiment has been a great success and am excited about what possibilities lay ahead. For my next experiment, I want to try taking a bit easier photo, and doing some more experimentation with the pfstools package. They are a bit more difficult to use, but the idea of not having to pay money for the tools is very appealing.

Now where to find my next photo...


Angie said...

Comment from Mike Barras:

Hey Chuck

I know the feeling. I just got my first taste of HDR and now I'm desparately trying to figure out how to get my hands on Adobe's CS2 software. I've been playing around with Elements2 for long enough..!!

Mike Barras

Angie said...

Comment from Will Key:

Have you looked at Cinepaint? It's a free opensource program available for Windows, Mac, Linux ... and it's used by the movie studios to do a lot of their work. Google can find it for you.
Who am I? Well, Ollie sent me here by mentioning 'the Thomas Boys'.