- Gold Sensor Mirror
- Sensor Mirror
- Red Sensor Mirror
- Ignitor Mirror
- Polarized Rose Copper
- Platinum Mirror
- Photochromic Red Sensor
- Red Sol-X Mirror
- Green Sol-X Mirror
- Gold Sol-X Mirror
Having multiple lenses at your disposal is crucial if you’re serious about shredding hard in all conditions, from whiteout to bluebird, or you just want to be as safe and prepared as possible on the mountain.
And given the number of goggles on the market designed to make swapping out lenses super easy, the number of lenses to choose from is growing. So what are your options, and what should you be looking for as you think about buying a new pair of goggles or another spare lens?
To begin to answer those questions, we’ve worked up a “cheat sheet” of the lenses offered by Smith Optics, and we are working up similar guides for other companies in the interchangeable lens game.
Different brands have different approaches to lens technology, but with almost 50 years of experience in making snow goggles, Smith is among the best in the industry. The interchangeability of the Smith I/O line allows a rider to bring a few specific lenses while riding and change them throughout the day as light conditions change.
Before getting into the lenses in Smith’s line, here is a brief rundown of how the tint and opacity of lenses is usually designated in the industry.
Any decent lens will block all ultraviolet (UV) light, but what differentiates lenses is their transmission of visual light. The Visible Light Transmission (VLT) measures the percent of the visual spectrum (wavelengths from 390-700 nanometers) that reaches the eye through a lens. The lower the VLT percentage, the darker the lens and the better suited it is for brighter, sunny conditions. With any given lens, a manufacturer (Smith included) will label it with a VLT value.
Different tints and mirrors alter the VLT of a lens, making it darker or lighter. A new class of lenses, termed “photochromic,” are made with photosensitive chemical compounds in the lens that actively change the lens’ tint based on exposure to UV light. This technology has the potential to change the game in snow goggles, but for now, it can’t compete with the level of versatility that two different lenses can offer. (See Will Brown’s analysis of Smith’s Photochromic Red Sensor later in this review.)
While VLT is the standard way for brands to rate how light or dark a lens is, over the years, we’ve found that VLT numbers don’t tell the whole story about how a lens performs. Combinations of different base tints and mirror coatings can make the contrast and color transmission of one lens different from another, though the two may have the same VLT rating. Looking at the VLT rating and manufacturers description alone, it can be hard to know which lens you’ll prefer. This guide ought to give you a better sense of how these lenses perform, how they differ, and which ones may work best for you.