Here is a Kickstarter campaign we thought you'd like, it's for a pretty cool universal lens cap solution. This lens cap will fit every lens with a diameter between 60mm and 150mm, so that will cover most non supertelphoto lenses, as well as protecting pretty much every lens mount.
Not only will it protect the glass on either side of the lens, it's also good protection from drops, as the rubber from the universal lens cap will give you some added protection.
Beyond drop protection, these caps will give you good protection from dust, dirt, water and pretty much anything else you may subject your lens to.
OUR MISSION: To Eliminate Photographer's Anxieties.
At some point, we lose lens caps and worry about the protection of our lenses. The Universal Lens Cap (ULC for short) is the best way to cover and protect your camera lenses. Period.
It's designed to fit every camera lens. Now, you can travel stress free knowing you won't loose your lens cap, it won't fall off, and you can go wherever and however you desire knowing you have the lens protection you need against the elements.