Camera lenses are precision pieces of equipment and should be taken apart only by a trained technician who will know how to put them back together. However, for individuals who like to know how things work, taking apart a camera lens can be very interesting. Different lenses have different elements. There a wide array of lenses on the market today, and each one is a little different.
Hold the lens so you can view the rear portion of the lens and mounting ring that connects to the camera. Locate the small Phillips screws in the rear of the lens. Most lenses will have four of these screws.
Unscrew the Phillips screws using a small jeweler's screwdriver. Set the screws aside.
Carefully lift off the mounting ring from the lens. If your lens is autofocus or a new lens that works through electronic contacts, look for a wiring harness that will be connected to the mounting ring. Use a pair of tweezers to disconnect this harness. Remove the mounting ring and set aside.
Unscrew the small Phillips screws on the side of the lens barrel. There are usually two of these screws. Longer telephoto lenses may have two sets of these screws, one set toward the front, and another set toward the rear of the lens. Remove the screws and set them aside.
Hold the lens in both hands, and gently pull apart. Some lenses may have an external ring at the front of lens that will need to be removed; this will become apparent as you take apart the lens.
Remove the internal lens and electronic elements from inside the lens by either removing the screws or prying apart the elements.
Each lens will be a little different in its construction. However, starting at the back of the lens with the mounting ring is your first step in almost every case. You should only take apart a lens that you have no intention of using again, unless you are very familiar with precision instruments and how to assemble them. If you are taking the lens apart to service it, be sure you are working in a well-lit area, and wearing cotton gloves to minimize the fingerprints you get on the glass.