I have the 7d
100-400L 77mm Ring
11-16mm Tokina 77mm Ring
50mm 1.2 L with 74 ring
I want to buy a 82mm Heliopan Vari ND. The idea is that I one day may buy the 16-35 L which is a 82mm ring. Maybe I dont and keep my 7d and continue with the 7d. I assume one day I will buy a Full Format. I am really worried to go crazy with 82mm is that a mistake to plan so far ahead? I just can never buy another filter this expensive...
I have 3x 7ds, 5dmk3, and a 1dx and used the 82mm Heliopan for my 16-35mm. This is a great filter. It is very clean and doesn't seem to cause any degradation to the shots that I take. It is quite pricy but to me it was well worth the money. I also have the 100-400mm 11-16mm and the 50mm. You may be able to buy a stop down ring so that the 82mm will fit the 77mm. I don't think they are too expensive. Hopefully this helped you out. I am a professional underwater photographer and I also do topside photography.