If you're a photography hobbyist with a nice SLR, you likely have more than one lens -- each with its own cap. If you're like me, you likely have lost more lens caps than you care to count -- and the stupid things ain't cheap! The obvious answer is a lens cap lanyard: you know, the $2 thingy you order from Amazon (or the $6+tax thingy you buy at your local camera brick-n'-mortar) that tethers the cap to either the lens or the camera.
I had issues with those lanyards. First of all, you gotta buy one for each different diameter lens. That seemed silly to me. Secondly, if you buy the kind that tethers to the camera, changing lenses can get messy. If you buy the kind that tethers to the lens, attaching gizmos (like I do) to the lens gets messy. Then there's the problem of the dangling lens cap getting in the way of the shot. There had to be a better way.
So I did a little mental algebra and made my own. Not only does the leash attach to all my lens caps with velcro, but that same velcro attachment is used to stash the cap on the camera strap while I'm shooting. One Lanyard to Rule Them All (my pile of unruly lens caps, that is).
And before you start telling me how inherently flimsy this is, please see the disclaimer on the last step! ;-)
Step 1: Assemble Ye the Materials.
1. Lens caps.
2. A couple feet of 1/8-inch grosgrain ribbon, or other sturdy string-like stuff.
3. Alcohol and cotton balls (or whatever) for cleaning.
4. Scissors you don't care about.
5. Small piece of coarse sandpaper for scuffing.
6. Sticky-back velcro for plastic surfaces.
7. Optional heavy tweezers or needle-nose pliers (not shown), if you don't have long, strong fingernails (I don't).
Step 2: Prepare the Lens Caps.
Use the sandpaper to lightly scuff up a spot on each lens cap where you will attach a piece of fuzzy velcro. Clean the roughened areas thoroughly with alcohol.
Step 3: Attach Velcro to the Lens Caps.
Cut pieces of fuzzy (NOT hooky) velcro, peel off the plastic backing (if you can -- remember, this adhesive was formulated for plastics. What a great idea to use plastic backing!) and apply firmly to the scuffed area on each cap. You can cut the thing any size and/or shape you want, really. Bigger would probably be more secure. If you have raised letters on your lens caps, however, avoid those.
Using the fuzzy part on the caps makes it less likely that the bottom of your camera bag will eat the caps off your lenses.
Step 4: Make the Lens Cap Attachment.
Make a knot in the end of the leash so it won't unravel with use. Cut two identical pieces of hooky velcro into strips that are roughly the width of the velcro on the lens caps. It's important that the strips are the same width; I just cut straight across a row of two. Peel the backing off the strips and sandwich the end of the leash between them, leaving a half-inch or so of the knotted end of the leash hanging free. Trim the ends of the "sandwich" (invariably there will be some alignment slop and exposed stickiness yuck -- kind of like your scissors blades are getting.)
Step 5: Measure Your Longest Lens.
Since one leash must work for all your lenses, it has to be able to reach from wherever you tether it, to the center of the lens cap of your longest lens. Plus whatever gizmos, multipliers, filters, and whatnot you're ever likely to clamp, screw, bayonet, twist, glue, duct tape, strap, or nail on the poor thing. Figure out about how long you need the leash to be, add at least an inch, and fold it double right at that measurement.
Step 6: Make the Camera Attachment.
Tape the doubled leash to a flat surface as shown in the photo. Tape it in two places, starting about 1/2 inch from the loop and leaving an inch in between the two pieces of tape. Cut two more strips of velcro -- this time the FUZZY part-- peel the backing off the strips, and sandwich the section of leash in between the two pieces of tape. Remove the tape, trim the ends of the sandwich and nip the corners off (they're sharp!!). Trim the excess leash tail near the velcro.
Step 7: And... Attach!
Loop the leash around your camera strap and pull the lens cap attachment end through the camera attachment loop. Slap it on the lens cap of your choice and -- you're set! To "park" the lens cap, simply remove it from the lens and stick the back side of the cap attachment velcro to the velcro at the other end of the leash.
Okay here's the disclaimer (and no, I am NOT a lawyer [shudder]): this system wasn't designed for robustness. You can toughen it up a bit by using heavy duty industrial velcro and making large attachment areas, but I wouldn't take it in search of rare species in the Amazon rainforests. Snapping pupfish from a creekside platform in Death Valley should work fine, though. Just be aware that velcro comes apart, and you can still lose lens caps.