Hi Dan,
What about taking lens UV filter? Is this H-1 that has the least or no effect on the image?
I read about this Langdsea filters on a Facebook group, someone was complaining having a focusing issues with this setup.
I spoke to a guy who gave his viewing filter and lens hood to a jeweler to notch it, so it can fit altogether on his 2.8F. I saw the picture, it looks good. He said he has it for some time, and it works great, no image quality issues, no flare, and no cleaning lenses anymore, just filters.
UV filters he uses are Rollei original. It has a letters Rollei-U-V, R III.
But when I search on eBay I see these are not the only ones from Rollei. There are few different kinds of UV filters, so I’m wondering which ones should I purchase just for the protection.