Unfortunately, I didn't catch the diamond ring phenomenon exactly; I was probably one or two seconds too late :( but we can still see some of the corona and two of the pinkish-colored solar prominences.  For this shot, I used my cropped-sensor Nikon D40 along with a 1970's vintage Celestron C-90, which has a 1,000 mm focal length, so that means that the effective focal length with a full frame sensor would be 1,500 mm.