<p>I don't have the 6, but have the 7II. I assume they will react similarly with filtering? I frequently stack at least two filters with the 80mm lens with no problems (vignetting) but do use a step up ring to 67 and use 67mm filters. I haven't tried stacking 58mm filters on the 80mm as I have standardized to 67 mm so can't really directly answer your question regarding 58mm. I have stacked 3 filters with the 67mm set up and haven't seen any problems. Hope that helps. </p>