Lens caps protect your camera lenses when the cameras or lenses aren't in use, whether you're storing or transporting them. Important factors to consider when buying lens caps are the right sizes for your equipment, and how you want them to adhere to your lenses.

Front Lens Caps

Although your camera probably came with lens protection, these small plastic accessories get lost easily. Having replacements is smart. In addition, you might also want to upgrade to metal caps, which provide more protection and eye appeal. Styles of front camera lens caps include:

Snap-on: Fits inside the filter ring of the lens
Screw-on: Screws onto the front threads on the lens
Push-on: Pops over the front of the lens and doesn't require threads
Proprietary: Made by the manufacturer to fit its specific lenses

Rear Lens Caps

Rear caps cover the part of the lens that attaches to the camera body. Use one to protect the lens when you have it detached from the camera for any length of time. Most rear caps are bayonet style and must conform to the bayonet design of the lens. Match the lens to the make and model of your camera.

Choosing the Right Lens Cap

You'll need some basic measurements and information to get the correct cap for your camera.

Size

The size of your snap-on lens cover is the same as the size of your lens. Look on the lens for a number and the symbol for diameter: a circle with a line through it. This number is the diameter of your lens in millimeters. If your lens has no such marking, use a metric ruler to measure across the center of the lens from the inside rim to inside rim. For a snap-on cap, measure the outside rim.

Brand

You can choose a front lens cover that's the same brand as your camera, or you can choose a generic one. You might choose an original part for aesthetic purposes, especially if the logo is front and center; but if this isn't a concern for you, the fit and function of a generic version will be very similar. Going generic generally results in cost savings compared to purchasing brand names, such as Fujifilm or Canon lens caps.

Accessories

Helpful lens accessories are lens cap keepers or lens cap holders. These devices attach the cover to your camera's strap, keeping the cap from getting lost when you take it off to shoot.