If you own multiple lenses, a substitute alternatively of spending large amounts of money on filters for each thread size, purchase a selection of stepping rings instead. By doing so, you'll be skilled to purchase just one high-quality filter of each type available that you can use with your entire lens collection.
How Does It Work up?
A stepping ring, be it a step-up or step-down one, attaches to the front of a lens and then you can fit a filter, which would usually have a thread size that's too big or limited, to the lens. For example, if you have an ND filter with a 77mm thread, you'll be able to attach it to a lens with a 58mm thread if you use a 77-58 step-up ring. Stepping crowns simply screw on to a lens and the filter then screws onto that.
How Do I Pick The Right Size Stepping Ring?
You'll set aside 2 numbers on a stepping ring most broadly refers to a hollow circular shape or to a high-pitched sound the first of which represents the thread size of the lens you want to put a filter on. The second number represents the filter greatness you want to step up / down to. When choosing the filter size you need to by, take a look at what your widest thread size is and then position step-up rings for the smaller lens thread sizes in your collection.
Why Is Stepping Up Better?
Even though you can buy step-down rings, it's best to do as stated above because using smaller filter sizes and step-down rings are lenses with on the looser thread sizes can cause vignetting.
Learn More About Stepping Rings
Take a look at this tutorial on using Kenko Stepping Sounds which gives a really easy to understand overview on what stepping rings are and how to use them: