Photographing Solar Eclipses - Digital Cameras
Author: Bill Kramer
Last update: Saturday, 18-Apr-2015 18:53:48 EDT
Digital cameras are great. They are a major improvement over film cameras for a number of reasons. While standard 35mm film is typically limited to 24 and 36 exposures, digital cameras can hold well over a hundred high resolution images. If you have a bad shot with a digital camera you just delete it instead of wasting the film space. Most digital cameras come with on board software that makes picture taking a breeze, you just point and shoot. Digital cameras are features on portable cell phones, can fit into a shirt pocket, or can be set up for direct communication to the Internet for live video feeds. Digital cameras take eclipse photography to a different level.
Consumer digital camera technology operate at a level desired for eclipse photography. Brightness ranges and density are now superior to most films. If you are not sure about yours, test it by taking a few pictures of the moon and see how they come out.
Types of digital cameras:
|Tiny - in a cell phone - great for capturing images of people before, during, and after the total phase of the eclipse. Does not do well with the eclipse itself since all you get is a blurry white area with a tiny black dot in the middle at best. Horizon colors and the rapid darkening can be imaged. Be polite when taking pictures during totality and stay still.|
|Small - pocket camera - excellent people pictures before, during, and after totality. Pictures of the eclipse will result in a somewhat blurry corona and black center. Can produce nice images of the horizon and sky colors, shadows, and silhouettes of eclipse chasers against the brighter sky. Make sure the flash is covered with black electrical tape or turned off!|
|Regular - SLR with removable lenses - professional grade cameras that accept multiple lenses or can be attached to telescopes. Using a wider angle lens these cameras are wonderful for before and after pictures, colorful views of the sky and extended corona, and silhouettes of eclipse chasers during totality. Zoom lenses will bring increasing details of the eclipse into view. The subtle shades of the corona, twisted details of streamers, and even prominences can be resolved clearly with sufficient optics.|
|Astronomical - replaces eyepiece on telescope - requires computer and possible cooling system, very sensitive to low light and much deeper depth of shades. Astronomical web cam type cameras designed for color photography of the planets and moon can be used even though they may be at too high a magnification for anything beyond prominences and detailing the visible edge of the moon. Typical lunar/planetary web cam set ups are meant to replace a 6mm eyepiece.|
- Turn off the review mode where the image is flashed on the display for a second or two. Those seconds add up during totality and there will be plenty of time to check out the pictures after the eclipse.
- Turn off the video display unless you are using it for focus. Do note that the light from the display will cause problems for anyone doing longer exposures with a wide angle camera set up behind you. Be polite, set the brightness to a minimum before totality.
- When using a zoom lens, set manual focus mode. Automatic focus rarely gets it right. On more automatic cameras you will need to override the focusing system and set it to or near infinity.
- Use manual exposure settings to shoot a range of exposures. If your camera has the memory available the best thing is to take more than one shot at each exposure setting. Shorter exposures will reveal the inner corona details and prominences. Longer exposures show more of the corona while the area nearest the moon washes out (is over exposed).
- Use automatic bracketing if it is available for your camera. Automatic bracketing will increase and decrease the exposure (or f-stop) saving your the need to change to those exposures. This feature is common on Digital SLR cameras.
- Set your camera to the maximum resolution or quality. In most cases this will result in fewer pictures per memory card since they take up more room. Bring extra memory cards and use a fresh one for totality if you are going to take a lot of pictures. JPG format is not the best way to store pictures before processing them. Use a native format for the camera such as RAW.
- Do not set a high ISO/ASA value. 200 to 400 is more than enough. Higher ISO values will result in more noise.
- Shoot dark frames before and then after totality for your image processing needs. Do not waste the precious minutes during totality making dark frames. Averaging the dark frames will provide an adequate processing base.
- For cameras with built in lens systems, use optical zoom and not the digital zoom. The digital zoom will result in artificial artifacts in the image. When using optical zoom be reasonable. Run some experiments in the months before the eclipse by taking pictures of the moon. Check the details and see how blurry or clear they appear. Reduce the zoom level if the image is blurry despite your best efforts to focus.
- Practice by taking pictures of the Moon during the various phases. This helps you learn how to use the important controls of the camera in the dark. In other words, you get a better "feel" for the camera.
- Recharge your batteries the night before. A back up battery is always recommended. Check your available power before the eclipse starts and make sure there is plenty.
- Check your memory card. You don't want to run out just as totality is taking place. Many eclipse chasers elect to use a blank memory card - make sure it is working by putting at least one or two pictures on it before the eclipse.
- Make sure your flash is off.
- Practice dry runs days if not weeks ahead of time. The full moon makes for an excellent test target.
Selecting a digital camera for eclipse photography
Digital cameras are the standard these days. Although film can produce a finer image of a total solar eclipse, digital cameras have become suitable. The primary differences between a picture of an eclipse taken with film versus a digital camera are the depth of the color, faster light gathering, the frequency of picture taking, and internal reflections/chip overloads.
The key feature to consider when purchasing a digital camera for eclipse photography is the depth of shading the electronic camera supports. The depth of shading is how many levels of a particular color can be stored. Cameras support millions of colors but may not always support the same shade depth. It is this feature that often produces a more vibrant picture in one camera over another. Color depth is often expressed in bits. Each bit provides an order of magnitude more data. An eight bit depth supports 256 color levels compared to one with 12 bits of depth supporting 4096 color shades. The number of theoretical color shades is two raised to the number of bits. Ideally you want as many as possible. Commercial cameras with 14 bits of depth are now becoming more common. These work quite well for total solar eclipse photography.
Compact digital cameras can produce eclipse images but the size of the image will be small when compared to digital cameras that can be attached to larger lenses and telescopes. It is recommended to use the optical zoom feature of a camera only. Digital zoom and other image enhancements are best accomplished at the computer after the event. Compact digital cameras are best for taking pictures of people before and after the eclipse - you can always trade those pictures for eclipse pictures from others.
The faster light gathering and frequency of picture taking when using a digital camera versus a film camera requires some minor adjustments in thinking. To take advantage of the faster picture taking you can set the camera in a burst type mode and turn off all the review features. Where as a film camera has to be advanced (manually or mechanically) a digital camera only needs to move the data from the chip to memory. Some cameras do this faster than others. Professional level cameras achieve this by providing buffers for maximum through put of a few pictures, then a delay, then another burst opportunity. A hidden advantage of digital is that the movement of the image is electrical and does not involve any mechanical items. Thus there is no vibration caused by that action. Another advantage of digital over film is the number of images you can obtain. Film is typically sold in 24 or 36 frame rolls. With a digital camera you can take hundreds of pictures before a new memory card is needed.
Internal reflections of cameras and optics are a problem with all image recording devices, film included. But digital cameras have additional sources of internal reflections that may cause a problem during the very high contrast diamond ring.