I just ordered the EOS M camera online and I started to order a Tiffen 58mm Variable ND filter. I was trying to get a size that I could use on some future lenses that have a bigger size thread. I need help on deciding how what sizes. I cancelled the Var ND and step up ring. Is that too big a jump up of 43 to 58? Should I get a smaller 52mm Variable ND and a 43 to 52 ring? Can I go even larger, such as a 72mm Var ND and a step up of 43mm to 72mm? There are some EF S lenses that have 58mm (my original idea) and then there are some L lenses that are 82mm that I might get later on. Should I get the Variable ND as 82mm and step up from 43mm to 82mm so the Var ND will always be useful? I that too much of a step up for such a small start at 43mm?

I'd go for a single step up ring, when possible. The're generally no problem with the size difference. The bigger problems are that the threads can be cheap on some adapters and that sometimes, adapters get stuck. Apparently, there are "adapter wrenches" or some such thing that act like an oil filter wrench and help you remove adapters and optical filters. I've never needed one though. I've always been able to coax the things apart.

The bigger size difference might actually be a good thing as such an adapter has more material and is less likely to get out of round.

thanx Jon. I forgot I had this post here. It should have been in the canon crop forum for the M.

alex