That $15 Kaiser job, or, a brief history of lens caps
As Vincent Vega once said, “That’s a pretty fucking good milkshake. I don’t know if it’s worth five dollars but it’s pretty f—ing good.”
There are only two reasons to buy a $15 lens cap (item plus shipping). One is that you are filthy rich. The other is that it’s a pretty f—ing good cap.
thousands hundreds of years that optical manufacturers have been making lenses, caps have been an afterthought. In the beginning, they were leather and promoted mold. Through the late 20th century, they were beautifully finished metal (or infrequently hard plastic) and predominantly relied on a friction fit to stay in place – and became useless as soon as they were dented or their felt linings became loose, grit-filled, or otherwise nasty. The 1980s brought the pinch cap; a thin plastic plate with spring-loaded tabs that engaged maybe 2 cm total of the circumference of the lens. This was easily knocked off and did not even effectively keep dust out. The 1990s version was the center-pinch variant, where the release mechanism could be operated even if a lens hood prevented the user from reaching the side-tabs. One almost has to wonder if the utter failure of lens cap design drove the UV-filter-as-protection craze, since it’s much easier to keep a filter screwed on than it is to keep a lens cap on.
To get back to the point, the Kaiser 206951 lens cap ($15 shipped at the usual places) is an excellent alternative. It is made of a semi-flexible plastic and basically stretches and suctions onto your lens. Size it 2mm larger than your filter size, and off you go. In testing so far on an X100, it fits snugly over a B+W F-Pro filter and creates an airtight seal that prevents pocket lint from getting in. Although it is not shown in the picture, many sizes of the 2069xx have lanyard loops so that they can be tied to strap rings or otherwise tethered so they don’t get away. This is a great example of a product that is well-designed, simple, and functional. Does it cost a little more than some Chinese pinch cap that you can buy for a buck, airmailed, because both the manufacture and shipping is heavily subsidized? Yes. But is it better? Absolutely.
Lens caps might seem like something simple and silly, but they fit into a category of product whose only value lies solely in its functionality. We would be lucky if every accessory were as well designed as that $15 Kaiser lens cap.