There are four main types of external damage sources to be concerned about.
- Dirt
- Scratches
- Shock
- Water
Dirt
Dirt is a daily challenge for your lens. Dust and other dirt on the surface of your lens will create horrible images. One stray spec of dust is probably not going to be noticed but if your lens is obviously dusty it can cause problems. Dirt causes even more problems as it is more difficult to remove from your lens surface.
Removing Dust and Dirt
For dust and lint, a simple microfiber lens cloth will remove the problem. Simply use light strokes working towards the outside of the lens. For mud or other stubborn dirt, you will need to use a cleaning solution designed for photographic lenses. If you use ammonia or another household cleaning solution you could permanently damage the lens. Most photographic lenses have a fine coat of oil on their surfaces. Eventually, this coating will wear off with repeated cleanings of any kind. Using a filter (see scratches) will help prolong the life of your lens.
Scratches
Scratches are a killer of your lens. There is no good way to repair them yourself. The best thing you can do is prevent scratches. The easiest thing you can do to protect your lens against scratches is to use a filter. A filter is a small piece of glass that fits in front of your lens. The original purpose of filters was to change the look of an image. However, many people use a polarizing filter or an UV filter as protection for their lenses. These filters have generally mild effects and are useful for general photography. Keep in mind that you are putting a relatively inexpensive piece of glass on a rather expensive piece of glass. Use high quality filters to avoid compromising your lens quality.
Shock
Shock is when your camera lens is hit or hits something else with considerable force. If you drop your lens or if someone slams a car door on your lens it will probably cause damage. Sometimes this damage can be repaired by an professional repair shop but it is almost always very expensive. The best way to protect your lens is to carry it (and your camera) in a padded camera bag, and to be aware of your surroundings. If you have your lens (and camera) out of the bag, pay attention to what is around you and be prepared to move your camera, and yourself, out of harm's way.
Water
Water is a mortal enemy to your lens. The electronic circuits and motors inside most of today's lenses can be destroyed by water. Also, Most lenses actually have several elements, or other lenses, inside them. If water gets on these internal lenses and drys it leaves water spots that you cannot clean yourself. To protect your lens from water damage there are several things to remember.
- If shooting in the rain, use a rain hood.
- When moving between temperature extremes, carry your lens (and camera) in a camera bag before changing temperatures to help prevent condensation inside the lens. Once moved to the new temperature, slowly introduce the new air into the bag.
- Be careful to avoid dropping your lens (and camera) into water.
- If your camera lens does get water inside of it follow these steps.
- Turn the lens so that the lens mount is down to help water drain from the lens.
- Wrap the lens in a very absorbent towel.
- Take the lens to the nearest professional repair shop immediately.
