NASA’ Earth Observatory

If you want to see what is happening on our planet, a good place to check out is NASA’s Earth Observatory website . The site posts an “Image of the Day” and the image above was taken on April 29th, the 10th anniversary of the site’s publication.

The photos are in the public domain and can be downloaded in a variety of sizes and formats. This photo shows two cyclones in the cold waters of the South Atlantic Ocean, just off the southern tip of Africa, where winter is approaching. The image was posted yesterday. A new feature on the Earth Observatory website is “World of Change” which will document how our world—forests, oceans, human landscapes, even the Sun—has changed during the previous decade. Read more!

The Practice of Problem Solving

Just because the weather is difficult, doesn’t mean you can’t practice your craft. For example, it’s been cloudy with sporadic rain for the past several days and today I decided to try my “50-foot Assignment.” This is a restriction that I occasionally impose on myself that permits me to take a photograph only of subjects within 50 feet of the door of my house. This is a useful way to train yourself to be a better observer of your surroundings. In addition, when a drizzle is threatening to become a cloudburst, it is also helpful to be able to get back indoors quickly. I decided to take a Nikon D-200 with an 18-200 mm zoom lens and a tripod. It was pretty easy to find something today, because a small patch of English Bluebells (not the native Virginia Bluebells, my subject on April 18) was at peak bloom in our back yard. I set the tripod low to the ground and looked for a decent composition. The advantages of a heavy cloud cover include a soft, even light and highly saturated color. The water drops hanging from the stems and blossoms were an added bonus.

Unfortunately, I was only able to stay long enough for 5 quick shots before the rain resumed and I was forced to duck back inside. After picking the best of the five and making adjustments in Adobe Camera Raw processor (a future topic), the final result is shown above. The ISO was set at 400 and the image was shot at 1/40th sec and f/5.6.

I was relatively satisfied with the outcome, given that I had such a short time to shoot. But I was frustrated that the short depth of field caused so little of the subject to be sharp. Using a higher f/stop would be one way to attack that problem, but it would have the undesirable side effect of causing the background to become sharper which would tend to distract from the subject. It would be nice if I could have greater control over the sharpness of the primary subject while keeping the far background completely out of focus.
An alternate approach might be the technique known as “Focus Stacking,” where a number of images are taken of the subject, each with a different part of the subject being in focus. The multiple images are then run through a special software application that merges them into a single image. In essence, the software selects only those portions that are sharp. Since I haven’t yet purchased one of these programs, it will have to be the subject of a future discussion, so stay tuned……
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