The first number is always the lens thread size, the second number is the filter size of the accessory. If the first number is bigger, it's a step-down ring. If the first number is smaller, it's a step-up.
Using Step Up And Step Down Rings To Take Better Pictures:
What is a step up ring
Step up rings, also known as adaptor rings, allow you to use filters and accessories that are not the same size as your cameras lens. Lenses and filters come in a large range of types and sizes and unfortunately they don't always fit together correctly. Fortunately there is a step up or step down filter for just about any need.
How step up rings work
Step up rings provide a way to fit a larger diameter filter or accessory onto a smaller lens. The step up rings screws onto your lenses threading and provided a larger thread with you can then attach other elements included more step up rings.
How step down rings work
Step down rings work in the exact same way but instead provide a way to attach smaller accessories and filters to larger lenses.
It is important to note that typically, the farther away from the lens you place a filter the worse the optics will be. It is always best to look for the thinnest adaptor ring that you can find as these will keep the filter close to the lens.
Package Includes:
37mm-49mm Step-up ring x 1
49mm-52mm Step-up ring x 1
52mm-55mm Step-up ring x 1
55mm-58mm Step-up ring x 1
58mm-62mm Step-up ring x 1
62mm-67mm Step-up ring x 1
67mm-72mm Step-up ring x 1
72mm-77mm Step-up ring x 1
77mm-82mm Step-up ring x 1
49mm-37mm Step-down ring x 1
52mm-49mm Step-down ring x 1
55mm-52mm Step-down ring x 1
58mm-55mm Step-down ring x 1
62mm-58mm Step-down ring x 1
67mm-62mm Step-down ring x 1
72mm-67mm Step-down ring x 1
77mm-72mm Step-down ring x 1
82mm-77mm Step-down ring x 1
