LENS CARE :: OUT, DAMNED SPOT!

Almost every photographer knows the frustration of looking at a print, or bringing up an image in Photoshop, and finding dust spots speckling the image like some flesh-eating disease. One spends hundreds, sometimes thousands of dollars on high-quality optics for a camera and yet the glass can become permanently ruined if one does not take proper precaution.

Dust has always been an enemy of most any optic from the glasses on one's face to the large lenses of space telescopes. Increasingly, however, digital SLR lenses have become more complicated and, as a result, so has their care. Cleaning methods that might have worked with the old analog lens one used in high school may well ruin the new digital lens for which one just paid $1,200. Extreme care must be taken to adequately preserve the investment made in such equipment.

An Ounce of Prevention

From the outset, one needs to understand that every camera lens is comprised of four basic parts: the lens elements, diaphragm, lens coating and focus mechanism. Any of those parts are likely to attract and hold dust. Therefore, keeping the lens and mount caps firmly in place and storing the lens in an appropriate dust-free container goes a long way in keeping down the amount of dust.

Even storage is not totally safe, however. Dark, humid conditions are perfect for the growth of lens fungus. Under normal circumstances, a lens that is being used on a regular basis is safe from this danger. However, combating this problem is relatively easy. Chances are the lens was shipped with a small bag of sillica gel or pellets. Sillica gel is a natural dehydrant. By keeping that small bag stored with the lens, air-born moisture is much less likely to become an issue.

Traveling also increases the dangers to lenses as changes in atmospheric pressure, weather, environmental conditions and general mishandling can all damage a lens while one is not looking. While keeping frequently used lenses in the camera bag may be more convenient, camera bags generally lack the protection a lens receives from being in its own hard-cased container. Such containers not only protect the lens from dust contamination, but also from damage due to inadvertent contact with other hard objects.

Lenses made specifically for digital cameras also carry the burden of needing to be kept well away from magnetic sources. This is especially true if the lens itself contains a digital component of any kind. Treat these lenses just as one would any computer-based media, keeping them well away from any electromagnetic field.

Good habits are tough to break

Many factors relating to good lens care are simply a matter of habit; things one can and should do every time we're dealing with our lenses that can help preserve the quality of the optics and extend the life of the lens. Five critical habits come to mind:

1. Avoid touching the prime element (front glass surface) with your fingers. Fingerprints on the prime element can be deadly, especially when not removed quickly. Modern camera lenses are coated with a very thin layers of chemical that both reduces reflection and increases the amount of light passed through to the media. This coating is very sensitive and prone to decay should any other contrasting oil or dust, such as is commonly found on fingerprints, come into contact with the element. Always handle the lens by its casing and wear surgical gloves when cleaning the lens.
2. Use a rain hood when shooting in any damp environment. This may seem common sense for rainy conditions, but many photographers forget that the light mist from a waterfall, or park fountain, or a heavy fog can all do severe damage to the lens. Chemicals present in most all water can etch the prime element. In less than 24-hours, droplets from a heavy fog can render a lens unusable. Don't take any unnecessary chances.
3. Do not use amonia-based glass cleaner or water to clean the element. Remember that coating? Most home window and glass cleaners contain chemicals that will completely eat through the coating in less time than it takes for one to put down the spray bottle and grab a rag. There are several good optical cleaners that do a good job of cleaning the lens while preserving the coating. Photographers do well to keep such cleaner in their camera bag at all times.
   
4. Only use a microfiber cloth on the prime element. Sure, it's really tempting when one is on location and sees a smudge on the lens to just wipe it off with a tissue, shirt tail, or a moist towelette from the local rib joint. None of those are entirely safe, however, and can do permanent damage to the lens. Tissues and towelettes are both paper based and can easily scratch the optic. Towelettes may also contain chemicals that would damage the coating. Cotton fiber, such as is found in many shirts and other garments, may feel soft, but can leave behind lint, which in turn attracts more dust. Even leather-based chamois, which is soft to the touch, can damage the prime element. Keep a clean microfiber cloth in the camera bag, next to the cleaner, and all should be safe.
5. Turn off the camera before switching lenses. This is a frustrating element for photographers accustomed to working with film cameras. Old guard photogs are quite proficient at reaching into their camera bags, grabbing a new lens and switching it out without missing a beat in their shoot rhythm. Digital cameras disrupt that flow. When the camera is still on, there is a very small amount of electric current running between the body and the lens mount. Swapping lenses with the camera still on has the potential to create a short, wiping out the electronics on either side. Digital cameras and lenses perform best when the lenses are changed while the camera is off, and the mounting cleaned before adding the new lens. No, this is not a time-efficient procedure, making the use of multiple cameras almost a necessity in fast-paced environments. Yet, one could lose the equipment entirely if the camera is continually left on while changing lenses.

Those five things should become so strongly embedded into a photographer's methodology that one doesn't need to think about them, they simply happen. On these factors there is little room for compromise.

Separate myth from fact

Much of the damage done to lenses is the result of well-meaning but misinformed actions of photographers following the advice of buddies or colleagues, who may not themselves be aware of the damage done to their own equipment. Here are a few of the more common myths that regularly pop up in conversation among photographers.

Myth: Pressurized air is the best way to clean loose dust from a lens.
Fact: Pressurized air is too powerful for most optical lenses. Loose dust can actually be blown into the coating and the seals, ruining the prime element. A bulb blower (not a blower brush) is the safest way to delicately remove loose dust from any surface of the lens.

Myth: Attach the lens cap to the lens to prevent loss.
Fact: Even a plastic lens dangling in the wind can whip around and scratch or even crack the optical. Keep the lens cap in a pocket and use it often, to be sure, but misused they can do serious damage.

Myth: UV filters are the best way to protect the lens.
Fact: After spending hundreds or thousands of dollars on a high quality lens, does it really make sense to distort that quality by slapping a $25 piece of glass on the front? While a filter does provide a modest barrier against dust, should it shatter in a fall the breaking glass is quite likely to scratch the optical behind it. At the same time, cheap filters distort the image, which is never desirable.

Myth: Soft-haired brushes are good for cleaning lenses.
Fact: No matter how soft the brush, one runs the risk of dirt becoming embedded in the bristles and scratching the optic. Brushes are more appropriate for non-glass elements but even then care must be taken to make sure the brush remains unquestionably clean.

Myth: Once discovered, lens fungus cannot be stopped.
Fact: Lens fungus (detectable by tiny lines stretching out from what appears as a single grain of dust) is actually quite treatable in most cases, but extreme care must be used. Using a microfiber cloth, place a small amount of lens cleaner on the cloth and use the softest touch possible to wipe the fungus from the prime element. If that fails to remove the fungus, one can use an electronic flash gun and fire it repeatedly into the prime element. In most cases the repeated flash kills the fungus. Photographers who live or work in more humid climates do well to fire a flash into their lenses on a fairly regular basis to help prevent fungus from forming in the inner elements of the lens.

Other factors of lens care are basic common sense. Do not leave lenses in a hot car. Do not expose lenses to rapid changes in environment (such as leaving a warm house to take pictures in the snow). Do not expose lenses to water. Protect lenses from blowing dust and sand. All of those items should be so obvious as to not require discussion. Yet, every year hundreds of thousands of dollars are wasted as lenses are ruined by simple carelessness.

While it is true that a good photographer is not limited by his/her equipment, good equipment helps good photographers take great pictures. Taking proper care of one's lenses is an important part of making sure your photographs are among the best.