Switch off your camera. Confirm that your camera is in "Off" position to prevent generating static electricity that may attract dust. Open the camera barrel on which the lenses are mounted. Press the lens release button to release the lenses. Dismount the lens from the barrel carefully. Hold the lens with a lens wipe or tissue to prevent it from catching dust or laying fingerprints on it.
Place the old lenses on a smooth surface, preferably in your camera bag. Pick up the new lenses using a clean lens wipe. Check the lens to ensure that no fingerprints, dust or water are present on the lens surface. Clean the lens to remove any specks of dust because these may ruin photos taken using your camera.
Handle the camera lens surface carefully by tightly grasping the lens barrel. Avoid touching rear and front elements to prevent leaving fingerprint marks on the lens. Shield your camera from wind, rain or dust if you are replacing your lens outdoors. Protect your lens from dust because it may destroy images produced by producing smudges that appear black or gray on your photo.
Mount the new lenses on the empty slots that held the old lenses. Match the mounting index dots on your camera and body to lock in the lenses. Check that the lenses are locked in tightly to prevent them from reeling out.