Step-up rings?

[ettin]

Hi all, Im getting a 12.5mm lens for my camera, which has uses 25.5mm filter, but the problem im running into is that 25.5mm IR cut filters arent available and im having trouble figuring out how to step it up without introducing vignetting. The only step-up rings for 25.5mm i have found are to either 37mm or 46mm. I already have a 49mm IR cut filter, so if anyone knows if a 25.5->37/46->49 would work without introducing vignetting it would be appreciated, otherwise, would using a 37mm IR cut filter be a better option? thx

 

[Big Mike]

It's sometimes hard to know what will vignette, until you actually mount it onto the lens/camera. Usually, you are safe when you step-up. It's when you step-down that you really run into trouble.