The Wisdom of Step-Up and Step-Down Rings
At first glance, purchasing a step-up ring is a simple, straightforward transaction―all you need is a metal ring that enables you to use a filter with a wider-diameter thread size than the lens on which you want to mount it. What’s not so clear-cut is why there are so many choices for a lens accessory that, on the surface, is so simple and basic.
The answer to the above is that the materials used to manufacture the ring, i.e., aluminum, hard-anodized aluminum, or brass, as well as the finish of the ring, i.e., side knurled edges or a smooth, less graspable surface finish, can make a big difference in how satisfied you may or may not be with your choice of step-up ring.
The opposite of step-up rings are step-down rings, which essentially do the reverse: enable you to adapt filter and lens accessories with smaller thread sizes to lenses with larger thread sizes. For example, attach a 52mm filter on a lens with a 72mm thread size.
Step-down rings are not as widely used as step-up rings because in most cases the smaller filter sizes result in vignetting. The exception to this rule is when using lenses and filters designed for larger-format cameras (i.e. full-frame) on smaller-format cameras (i.e. APS-C and Micro Four Thirds). In these cases the smaller image field will often negate any vignetting or image clipping.
$5 or $50 for a stepping ring? Why?
Stepping rings are available from numerous manufacturers and can cost anywhere from a few dollars to well over one hundred dollars. Why, you may ask, does a step-up ring from one company have one price tag, while “the same ring” from other companies can cost upwards of ten times the price? The truth is that the rings are not the same.
Stepping rings, as mentioned above, can be made from a variety of materials, typically aluminum, hard-anodized aluminum, or brass. While stepping rings of all materials essentially perform the same function, rings of differing prices will often relate more to the performance, consistency, durability, and reliability of a given ring.
Aluminum rings cost less than, but are not as strong as, their hard-anodized aluminum counterparts. Aluminum is a softer metal and more prone to developing dings from impacts, as compared to brass―and brass generally costs more to manufacture. What is a bit confusing, is which of these materials—aluminum (plain or hard anodized), or brass—is best.
While stepping rings of all materials essentially perform the same function, rings of differing prices will often relate more to the performance, consistency, and reliability of a given ring.
Does it matter if the ring is made of brass or aluminum?
The product descriptions of the stepping rings typically contain the words “aluminum,” “hard-anodized aluminum,” or “brass.” Knowing what a ring is made of should be an important consideration when choosing stepping rings (and equally important when choosing filters). This is because if the threads of what you’re attaching are made of the same material as the stepping ring and are not machined to the same high standards, there's a risk of “galling,” or in the colloquial of camera-repair shops, you’ve got a jammed filter on your hands, as we explain below.
According to the rules of metallurgy, and Mrs. Zuckerman, my grade-school science teacher, it is possible, in some cases, to create friction between two pieces of alloy of the same hardness and composition, such as aluminum to aluminum, which could lead to galling. This typically occurs when trying to screw a ring or filter at an angle other than straight into the lens threads, and can be exacerbated by rings and filters that are machined to lesser standards.
"What’s not so clear-cut is why there are so many choices for a lens accessory that, on the surface, is so simple and basic."
The easiest method of reducing the likelihood of a jammed step-up, step-down, or filter ring is to buy items that are machined to the same high standards. It's worth keeping in mind that less expensive rings are most likely not machined to the same standards as premium rings, which can easily increase the likelihood of a jammed ring or filter.
The barrels of pre-autofocus film-era lenses were invariably made of aluminum, and in select cases, brass. These days, determining what a lens barrel is made of can be tricky. Kit lenses are often made from some form of polymer, while many premium lenses feature threads made of harder alloys, including aluminum, with forward edges made of other materials, which are not as prone to galling issues.
One helpful feature that select manufacturers incorporate into their rings and filters is side-knurled edges that make it easier to grip the rings or filters when attaching or removing them from the lens threads.
Choose the right rings for your needs
If cost isn’t an issue, brass rings are more reliable, last longer, are less likely to warp, and can be used with most other metal alloys with little fear of galling. For the record, I’ve owned the same set of brass step-up rings for more than 30 years, and I use them to this very day. It’s not that rings made of the same materials as the lens barrel or filter will jam every time you try to attach them. In fact, they may fail on you on the rarest of occasions; it’s just that it’s most likely to happen at an inconvenient, never-to-happen-again moment in time. And that's when you'll wish you had the right combination of rings and filters.
Ideal candidates for brass step rings are professional photographers who cannot afford product failures on the job, who vary and use different filters, who take them on and off all the time, and take every advantage to achieve their vision. A professional photographer is better served by using well-machined brass, which decreases the likelihood of galling, and helps protect their investment in filters and stepping rings.
Why and when you would need a step-up ring
If you own an interchangeable-lens camera system, chances are you own more than one lens. What’s more, there's a good chance the filter thread diameter sizes of one or more of your lenses differ from the other lenses. For example, two lenses might have 58mm thread sizes, while the third lens might have a 49mm, 62mm, 67mm, or 77mm thread size. Then again, each of the thread sizes might be different. And the more lenses you own, the more likely this is going to be the case.
Once you go beyond the best-quality protector or UV filters to serve as basic protection, you may wish to use an additional filter such as a Circular Polarizer, ND, Graduated ND, etc.
"You could say stepping rings are a win-win solution that should please both your wallet and your gear-besieged shoulders and back."
The starting point for configuring a step-up ring system is to establish a pecking order from widest diameter thread size to the smallest. As an example, if you own three lenses—one with a 52mm thread, another with a 67mm thread, and a third with a 77mm thread—you want a filter to fit the widest diameter thread size, in this case 77mm, and a pair of step-up rings, 67-77mm and 52-77mm, to couple the larger 77mm filter to the smaller-diameter thread sizes.
Although thread size doesn’t affect image quality, it does have an impact on the number of filters and lens accessories you have to keep on hand, regardless of whether you are taking pictures indoors or out. Rather than purchasing multiples of every filter and lens accessory to go along with each of the thread sizes, consider purchasing a single, high-quality filter to fit the lens with the largest thread size along with step-up rings to adapt the larger filter to the lenses with smaller thread sizes.
It’s hard to knock the advantages of stepping rings. Simply stated, if you own lenses with varying filter-thread sizes, stepping rings weigh and cost less than multiples of comparable glass filters and lens accessories. You could say stepping rings are a win-win solution that should please both your wallet and your gear-besieged shoulders and back. While stepping rings can be stacked, it is best to use as few rings as possible to reduce the chances of vignetting or ghosting.
Why and when you need a step-down ring
The opposite of step-up rings are step-down rings, which essentially do the reverse: they enable you to adapt filter and lens accessories with smaller thread sizes to lenses with larger thread sizes. For example, they allow you to attach a 52mm filter to a lens with a 72mm thread size.
Step-down rings are not as widely used as step-up rings because, in most cases, the smaller filter sizes result in vignetting. The exception to this rule is when using lenses and filters designed for larger-format cameras (i.e. full-frame) on smaller-format cameras (i.e. APS-C and Micro Four Thirds). In these cases, the smaller image field will often negate any vignetting or image clipping.
For further reading about the filters to which you can apply step-up or step-down rings, click on the following links: