For observation and photography of sunspots and granulation only in conjunction with a Herschel wedge or Astro Solar film. This filter cuts out a narrow spectral range at 540nm from the solar spectrum. At this wavelength have granulation and the structure in the sunspot their highest contrast.
For safe visual observation is the use of 3.8 AstroSolar an IR blocking filter required!
Baader 1.25 "Solar Continuum - Filter stacked - 2 filters for even higher contrast