We have a full solar eclipse coming on May 20th, 2012, and if you want to be prepared to record the event here are some tips on photographing the sun directly for an eclipse shot.
Some people try to put those “eclipse viewing” shader glasses that are being sold in novelty stores and over the Internet over their camera lenses. This can work OK if you have a small point-and-shoot, but the results won’t be staggering because you can’t capture both the sun and the surroundings at the same time using this technique. If you have a decent digital SLR, you might get better results without using a solar filter on the camera (unless you mean a polarizing filter, which actually would help in this case).
The technique is to use a tripod and ideally a prime lens that has a wide range of F-stops, and then use an HDR blending technique to produce the final output. The shape and number of leaves in the diaphram of your lens will determine what type of flare you get from the Sun, and typically a non-zoom prime lens will have a more pleasing shape to the flare produced by the sun in a sun shot. You will want to select a lens that has an equivalent of a short-medium telephoto, between 50mm – 135mm on most consumer SLRs (1.6 magnification such as the Canon Rebel cameras), or between 85mm and 200mm on a full-frame camera such as a Canon 5D or a Nikon D700.
Frame your shot nicely including a tree, buildings, people, or anything to give it scale. Now you need to take at least two shots from the same position without disturbing the way the camera is pointed. Ideally you should be shooting using Raw format, which gives you the most flexibility to adjust exposure and brightness in the post-processing session, but if you aren’t already using Adobe Lightroom or Apple Aperture it may be easier to just shoot in JPEG format.
You will take at least two shots to compose your final output. One of these shots will be at a very closed F-stop (larger number) and a fast exposure to capture the sun. This is probably at the limits of your camera’s exposure speed, in the 1/1000 – 1/3000 range, and it might need to be even higher, such as 1/5000 or above, if you have a particularly long lens which fills more of the frame with the sun rather than the sky or surroundings. The other photo will be at a slightly more open F-stop (smaller), and a still quick but much slower exposure, perhaps 1/250 to 1/500. Remember not to look at the sun through the viewfinder if you are using a long lens which will amplify the amount of light collected from the sun and shine it right on your eye. Use your cameras live-view to set up the shot, or take several shots and look at the results to adjust the tripod. The amount of light falling on the sensor determines how excited each tiny sensor gets, and some camera sensors tend to stay a little “hot”, which can produce noise in your next shot, so it helps to give the sensors several seconds after using live-view or taking a shot to let the sensors cool off.
Many cameras include a feature known as depth of field bracketing, which allows you to tell the camera to take 3 or 5 shots at different F-stops and then automatically figure out the exposure. This automates the process above.
Finally, use photoshop or similar software to combine the two frames. You should be able to take the sun from the first fast shot and the landscape from the second shot. You can also use software designed for just this kind of blending, or do a web search for “HDR Technique”.
A second technique is to use a fill-flash to illuminate the close-up surroundings while allowing the exposure to be short enough that the sun doesn’t overexpose the shot. I haven’t detailed that process here, because it typically requires more equipment, and is more difficult to set up correctly even with full sunlight. With the changing light-levels of an eclipse, this is a very difficult process.
You can practice this before the eclipse to make sure you’ve got it down. Flickr is a great resource for finding and sharing images of events or practicing techniques, so if you want to be well-practiced before May 20th, try taking some HDR of your own and find an HDR group on Flickr to point people to your shots and ask politely for criticism. Have fun!
