Hi
I have recently purchased this set which includes two 305mm cells and one 575mm cell, the iris scale is in millimeters, could anyone tell me the aperture settings for each cell seperately and for the combinations or indeed the formula so that I can calculate for myself, also I have read posts on this forum which have mentioned other focal length cells in different sets, has anyone come across anything longer than 575mm, do all the cells have the same mounting thread as I am thinking I might pick up another set with different focal length cells?

Any info greatly appreciated