What I see through a NIKKOR lens is never an issue; it's whatever I choose. But what I see on a NIKKOR lens can be another matter, and that's what brought me not long ago to the office of Nikon senior technical manager Lindsay Silverman. As a writer and editor in the photo industry, I'm well aware of Lindsay's expertise.

My timing was perfect: on a side table were several NIKKORs. I picked up the AF-S NIKKOR 200mm f/2G ED VR II. "You know what confuses me?" I said.

"String theory?" he said.

"That, too," I said, "but in this case, it's the VR II designation. I see the Roman numeral II after VR in the written description of this lens, and after the G on the lens barrel, and I take it to mean that this lens offers the second generation of VR technology."

"Common misconception," Lindsay said. "There is a second generation of VR image stabilization technology that allows hand-holding the camera at up to four stops slower, but that designation appears in lens instruction booklets, on spec sheets and with lens information at NikonUSA. The Roman numeral you see in the printed name and on the lens barrel means the second generation of that particular lens."

"Like this one," I said, indicating the 200mm lens I was holding.

Nikon NIKKOR 55-300mm Lens Barrel

The AF-S NIKKOR 200mm f/2G ED VR II. The Roman numeral indicates
it's the second generation of the AF-S 200mm.

"Right," he said, "and it features VR II technology." 

"But how would I know that?"

"From the product description at NikonUSA or the manual for the lens."

"Okay, so a Roman numeral II on a lens means second generation of that lens—and that's all it means."

"Right," he said. "Here, let me take you through the rest of what you're seeing on our lenses." He reached over and got the AF-S NIKKOR 24-120mm f/4G ED VR.

Nikon NIKKOR 24-120mm Lens Barrel

The AF-S NIKKOR 24-120mm f/4G ED VR.

"Right above the focusing ring and next to the Nikon name is the distance indicator window, which tells you in feet and meters where the lens is focused at any given point. To the right of the distance indicator window is the letter N, meaning the lens has Nikon's Nano Crystal Coat, an incredibly effective anti-reflective coating.

"There can be other notations, though." He picked up an AF-S DX NIKKOR 55-300mm f/4.5-5.6G ED VR.

Nikon NIKKOR 55-300mm Lens Barrel

Any Lens that features the letters DX, like the AF-S DX NIKKOR 55-300mm f/4.5-5.6G ED VR,
is optimized for Nikon DX-format sensor cameras.

"Here there are the letters DX next to the Nikon name, which means this lens is optimized for cameras with a DX-format sensor—the D300S or D7000, for instance. If you don't see DX, then the lens is optimized for FX-format cameras, like the D3X, D3S or D700.

"The other notation is an indicator of the type of specialized glass used in the lens," he added, showing me an AF-S NIKKOR 28-300mm f/3.5-5.6 ED VR.

Nikon NIKKOR 28-300mm Lens Barrel

The AF-S NIKKOR 28-300mm f/3.5-5.6 ED VR features ED glass and a variable aperture.
The f/stop changes from f/3.5 at the 28mm wide-angle focal length, eventually
reaching f/5.6 at the 300mm telephoto end of the range.

"ED means extra-low dispersion glass—it's an optical glass Nikon developed for correction of chromatic aberrations. If the lens features both Nano and ED, the ED designation moves down to a part of the descriptor text—that's the line below the Nikon name and the indicator window."

Then he took me through that line for the 28-300mm lens.

"AF-S is for the silent wave motor used in NIKKOR lenses for fast, accurate and, as you'd expect, super quiet AF operation. Next, the word NIKKOR—no explanation necessary. Then comes the focal length of the lens. Here it's the range of this particular zoom—28-300mm. Then comes the maximum f/stop—the largest opening of the diaphragm of the lens. On this lens there are two numbers—3.5 and 5.6, which means it's a variable aperture lens: the f/stop varies as you zoom the lens. The f/stops are always indicated as fractions on the lens, by the way—that's why you alway