I love the fact that the moderators for Cloudy Nights thought of having a dedicated forum for the North American Total Solar Eclipse 2017. I am going to work hard to try to contribute to this forum. Eclipses are my passion.
I am a private practice plastic surgeon that has always been involved in out-reach education, both in my profession, medicine, and in my hobby astronomy.
I have observed 3 previous total solar eclipses, 2 on land and 1 on a cruise. Since 2001, I've studied in great detail everything Fred Espenak has written about eclipse photography. After each of my eclipses I would analyze what went right or what went wrong. For the purposes of teaching, I break down solar eclipse photography into 4 simple steps. I try to demystify the preparation.
For 2017, I am determined to help as many 1st time eclipse observers and photographers to be successful. In preparation for this eclipse, I have been giving a comprehensive talk about eclipse photography. I am designated as a NASA Subject Matter Expert on this eclipse. I have given my talk to the NASA Solar Science Group at the National Space Science Technology Center in Huntsville, Alabama. I've given it to the Birmingham Astronomical Society in Alabama. I had the opportunity to coach the team from the Smithsonian Air and Space Museum that is going to Missouri to video stream the eclipse back to the Museum. In June I am scheduled to give a talk at the US Space and Rocket Center in Huntsville. I will continue outreach right up to the eclipse.
My plan is to add posts to this forum that pulls screen shots of slides from my talk.
The Four Steps are:
1. Effective Focal Length For Eclipse Photography
2. Understanding Eclipse Camera Exposure Based On Filtered Full Disk Sun Images
3. Relating That (Step 2) To The Exposure For Baley's Beads and the Diamond Ring
4. Bracketing During Totality
I will then supplement with posts on proper C2 and C3 photography timing. Partial phase phenomena sequence imaging. Tips for video. Tips for wide angle shots. Maybe we can also discuss the partial phase phenomena, one of my favorite parts of an eclipse.
Today I am posting Step 1 - Effective Focal Length For Eclipse Photography
I have attached 6 slides that are self explanatory. The bottom line is that you must understand that there is a sweet spot for focal length with solar eclipse photography and that is an effective focal length of 800mm to 1,200mm. If you are too short you will have to crop in a lot for corona detail. If you are too long you will cut off the outer filaments of the corona with the longer shutter speeds (Step 4). Actually, right at 1,000mm is perfect.
The 1st 4 slides are an overview of the difference between full frame chip digital SLR cameras and small chip digital SLR cameras and the effect on effective focal length. You must understand this about your particular setup. You must practice now, with a solar filter on your gear and determine the Sun disk image size for YOUR setup (slide 6).
The 5th and 6th slides are the 1st keys to success. These slides have one of my totality photographs overlaid on a film image representing some common focal lengths. So the point is, it does not matter what glass you will use or what camera you will use (crop factor or not), as long as you will be in the sweet spot for your setup (slide 5).
Thanks for reading this. I will work on the Step 2 post.
YouTube channel Foxwood Astronomy