Step-up rings allow large filters to be used on lenses with smaller diameter filter threads; the filter will be much larger than the diameter of the lens. Use of step-up rings is often mandatory and routine with shorter focal length or wide angle lenses in order to prevent vignetting.
Step-down adapters allow smaller filters to be used on lenses with filter threads of larger diameter. This may result in vignetting so their use is normally not recommended.
If you have a question or need some information please provide us some data. Our sales team will callback as soon as possible!