.... cleaned it with one of the lens clothes that my opthomologist hands out after my eye appointment for my glasses..I collect these little soft squares whenever I have an eye appointment because they are made for the purpose of cleaning lenses....Houston is a very humid climate and after doing some night photography the lense seemed sticky and so I buffed with the soft cloth...I did not add any sort of cleaning fluid...but I noticed when I had finished that there was the faintest blue smear across the lens surface....
First of all, those coatings on the front of your lens are a whole lot tougher than you might think!
But the multicoatings on lenses (and on filters!) can make it tough to clean off some things... such as the somewhat oily residue that salty, humid air tends to leave behind.
I usually DO NOT use filters to "protect" my lenses and consider it pretty silly to think that a thin piece of glass is going to provide much meaningful protection. In fact, I've seen lenses damaged by broken filters, when the shards of glass from the filter gouged the front of the lens. Plus, there are a lot of lighting situations where a filter can cause increased flare and chromatic aberrations... even focus and sharpness issues in some cases.
However, I DO have "protection" filters available for uses in certain situations, and one time I DO often use them is when shooting at the coast where salty sea air tends to leave that difficult-to-remove, oily film on everything (...also in dust storms and a few other circumstances). Some people choose to leave filters on all the time. Others leave them on most of the time and remove them in certain situations where they might do some harm to their images. I just do the opposite and only installl them when I feel they might actually do some good, either protecting the lens or improving the image.
I am not trying to talk you out of using a quality protection filter on your lens. If it makes you feel more comfortable getting out and using it... by all means do it. However, a filter is not a very good replacement for using a proper lens hood while shooting and a lens cap when storing your gear, both of which will give better protection than a filter ever could. A hood and cap are actually even more needed with the filter... to protect it too!
And I strongly recommend using high quality, multi-coated filters that do the least "damage" to your images in most situations. Among others, B+W MRC and Hoya HD are some good ones. These aren't cheap, but they're worth it.
You'll also still need to do cleanings. In fact, once you install a protection filter you'll have two more surfaces to keep clean, although the back side of the filter and front side of the lens may not need cleaning as often. And you'll find that most filters can be as difficult or even more-so to get clean, than the lens itself. So to be set up for proper cleanings, you need:
1. A bulb blower to puff away loose dust.
2. A brush or dry rag to gently remove any remaining dust particles.
3. A quality lens cleaning solution such as Purosol, ROR, Zeiss, Eclipse or similar.
4. Some micro fiber cloths to use both slightly dampened with the cleaning fluid and to dry off the lens after a wet cleaning.
5. Alternatively, quality single-use optical cleaning wipes such as Pec Pads can be used instead of micro fiber cloths.
6. A Lens Pen, to be used as a final step to clear the slight haze the solutions leave and polish the lens to be more resistant to dust re-adhering to it.
Use those in the order listed, to clean your lenses and filters.
Never drip solution onto the lens itself. You don't want it seeping into the lens. Just use a few drops to dampen a clean, lint-free cloth or the optical wipes.
Do not use common cotton swabs (Q-Tips), they tend to shed fibers that can get stuck in inconvenient places.
Also do not use cheap "lens tissues", which are often made from wood pulp that might contain minerals that can scratch lenses.
Those micro fiber cloths can be washed and reused. Just be careful that no fabric softener is used on them during the rinse or drying process... that can cause smearing like you are seeing now.
With a digital camera, we also need to clean the sensor occasionally. Well, actually we clean a filter permanently installed in front of the sensor. Some of the same products and a similar process are used to clean sensors.
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
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