(Photography "outside the box")
[click on the image for a larger view]
I have been curious for a long time whether it would be possible to photograph the international space station as it passed overhead. I had been watching the NASA website and making notes of when an opportunity might come with the ISS passing in close proximity to my location. It is only visible if it passes close by, and then only when it's dark outside and the ISS is illuminated by the sun. On Thursday evening 6/24/10 at 9:54pm that opportunity came, and it was supposed to be visible for around 4 minutes starting when it was about 800 miles away and eventually passing as close as 227 miles.
Since the weather was clear, I went outside about 5 minutes prior to the beginning of the viewing window with a 500mm f4 lens and 1.4x teleconverter mounted on a Canon 40d body. My plan was to try and hand hold the rig using autofocus and see if I could lock onto the 'dot' as it passed overhead. I made some practice shots of the moon to try 'guestimate' the correct exposure, and I decided on 1/250, f8, iso 400. I would be using manual exposure, but with autofocus and image stabilization mode 1, since it would be more of a 'hold it steady' motion than a panning motion. The ISS was easy to see with the naked eye as it approached, and I was able to locate it in the camera viewfinder and fire off some shots while trying very hard to keep the bright dot in the center of the frame as it streaked across the sky. I was surprised that the 40d actually locked focus very easily most of the time.
Of a couple dozen shots, only a few taken when the subject was the closest showed any real detail. The image shown above was my best shot. It is shown here as a 100% crop, but it is actually about 1.58 times actual size due to opening it in photoshop at a resolution higher than the native resolution of the camera. (You must click on the photo to see it actual size).
I tried a second attempt Sunday morning at 4:57am, but this time with stacked teleconverters hoping to get an image twice as large with my 1400mm rig. Since autofocus is not an option when using 2 teleconverers, I used manual focus and pre-focused on the moon in order to accurately set the focus at infinity. When the ISS came into view, I found it in the camera viewfiner and took some shots. But as it got closer and near the sweet spot where I could get a closer photo, I lost it and was unable to find it again looking through the camera even though it was clearly visible to the naked eye. The added focal length meant that I was looking at a much narrower slice of the sky when looking through the lens than on my first attempt. This proved very frustrating, but at the same time it was a learning experience. Hopefully I can do better next time.
[click on the moon image below for a larger view]
