HDR Photographs

Still in a holiday mood, I have been playing with Photomatix trying to convert “normal” pictures into high dynamic range pictures (HDR – read more here and here). At the moment, I am certainly not even up to the beginner standard but I have learned a few things in the last couple of hours. Simply put, HDR is taking multiple pictures of the same scene at different exposures, then combining these exposures to make a single image.

For simple HDR type images, the most common methods (on windows, Linux users get a different set of joy and I have no idea about Macs) are to use Photoshop or Photomatix. In newer versions of Photoshop you have the option to either play with layers and blend your images (can get fantastic results but can also be very hit and miss) or use the Merge to HDR option (File -> Automate -> Merge to HDR in CS3). Sadly, personally, I have never had much success with the automatic option but you might manage it.

Alternatively there is a bit of software called Photomatix (Pro costs $99, Basic is Free) which does a similar job but includes “Tone Mapping.” Peter Hasitschka’s page gives more details (along with some fantastic images) so I wont go into detail here. Needless to say, the tone mapping can give you some amazing results, although I have only been playing with this for the last 30 minutes or so. So far it is worth every penny.

One issue I have discovered – and for seasoned HDRers this may be so basic as to be comical, or I may be getting the wrong end of the stick – is the choice of exposures is key. I have been playing with a picture I took today, and I have it in a variety of exposures — -3, -2,-1, 0, +1, +2, -3 — and I’ve been experimenting with it in Photomatix. Over and over again, the images merged with the over exposed images included came out terrible. To give an example of what I mean:

The Original Image This is the base image, taken on a Nikon D80 set to f/3.5 and 1/2500 sec shutter speed, using a 24mm lens. The image is pretty average and this was the “0” exposure – no extra compensation has been taken. In addition to this image, three under exposed and three over exposed images were collected.

From this, the first HDR image was compiled:

HDR Image Using the Full Range of Exposures

Well, as you can see it is not exactly a success. Fortunately, I was stubborn enough not to give up on Photomatix and I tried many different settings (mostly variations in the tone mapping window). Eventually I tried to merge the HDR without using any of the over exposed images and this is the result:

HDR image - underexposed images only

As you can see, it is a massive improvement over both the base image and the first attempts at an HDR picture. While I am not going to pretend it is anywhere near the wonders shown on Peter Hasitschka’s site or the Apogee Photo Magazine site, it is nice enough for my purposes! It is also good enough for me to want to carry on experimenting with this type of imaging and hopefully, eventually, I will work out how to get some breathtaking ones.

My initial suspicions about this particular picture are the base exposure was too high for Photomatix to be comfortable with – which is why it has massively overexposed the end HDR picture. Still, now I know, I can play with the other pictures I took.

[tags]Technology, Photomatix, Photoshop, Digital Camera, Camera, Digital Pictures, Digital SLR, Photo Editing Software, Photos, Photographs, Pictures, HDR, HDR Images, Nikon, D80, Peter Hasitschka, Apogee Photo Magazine, Photo Editing, Digital Photography, Digital Photographs, Adobe[/tags]