ND filter question!

[Miti]

Hi everyone

I have just bought an B&W ND 67 mm Filter for my 100 mm L macro lens. What can I do in order to be able to use it on my 17-40mm L which is 77 mm? Would it be okay an 77-67 step down ring?

 

[bobandcar]

If you could use one then you would have a black circle around your photo. Also you would loose more light than what the nd is rated for.
Would have been better to buy the 77 and step up to that when needed.

 

[Miti]

yeah you are right ....unfortunately I have noticed to late the error. How stupid I was. I had to buy an 77mm straightforward. It looks like nothing can be done then,,,