I searched the internet for some assistance in removing the digital noise using the GNU Image Manipulation Program (GIMP), and stumbled upon a well written post about how to remove digital noise.  The technique makes use of the GREYCstoration plugin for the GIMP.

I use the GIMP on Kubuntu Linux, and wondered if there was already a package created for GREYCstoration.

$ apt-cache search greyc
gimp-plugin-registry - A repository of optional extensions for The GIMP

I found it!  So I installed it:

$ sudo apt-get install gimp-plugin-registry

After restarting the GIMP, here are the results:

Low light photo (scaled)

Low light photo (GREYCstoration, scaled)

I usually use a longer lense (300mm) to get in close, and didn’t realize how much shaking is going on when I am photographing something.  Since a lot of birds eat in the morning or evening, and the setting is my back yard which is wooded, the birds are not in full sun light.  The other challenge in a wooded environment is auto focus.  Too many things for the auto focus to focus on, and how does it know I am looking at a bird?

1) Focus Problem  2) Lens Shake  3) Missed the Bird

So here is what I do:

1. Increase the ISO.  I set my Canon Digital Rebel XTi to ISO 1600.
2. Use shutter priority – TV – mode.  Set the shutter speed to 1/125s or faster.
3. Use the rapid fire – AI Servo – mode for taking lots of photos very fast.
4. Use manual focus (sometimes).

I normally only have to use the Auto button. Sometimes I have to change an individual channel. Sometimes I can set the Black Level or White Level by selecting objects in the photograph. Sometimes I just move the little triangles under the histogram. The left triangle should be just at the start of the left side of the histogram. The right triangle should just be at the end of the right side of the histogram. The middle triangle adjusts the gamma value.

Image above before adjusting levels. Image below after auto adjusting levels.

I learned something new about photography while eating lunch today and browsing flickr: HDR. HDR stands for High Dynamic Range and is a photography technique used to represent the wide range of intensity levels as can be seen by the human eye. It is normally done by shooting multiple exposures and then blending the exposures in a photo manipulation program like the GIMP. Some of the HDR photos I saw today are really stunning and colorful. A lot of the HDR images are just tone mapped and look fake.

Although not necessarily the same as HDR, I sometimes fix a photograph using an exposure blending technique. I use a Neutral Density filter gradient technique in the GIMP. I would like to explore using HDR in my photography. Perhaps I will use pfstools. pfstools are open source applications for reading, writing, manipulating and viewing high-dynamic range (HDR) images and video frames.