One way to keep fingerprints off of a quality lens is to keep a filter on the lens at all times. If you prefer not to, or get a print on a lens while changing filters, this small tool will come in handy. The Lenspen offers two cleaning options. On one end, there’s a retractable dust brush. I just extend the brush, and sweep away any visible dust particles. I also use the brush every time I replace the lens. Dust particles almost always appear around the area where the lens and camera body meet. I make sure to clean up this area before removing and changing lenses, thus reducing the chance of getting dust on the sensor.
The Lenspen’s other end, has “a special non-liquid cleaning element” that can be used for more aggressive cleaning. Wipe it over the lens and magically watch fingerprints disappear. The manufacturer explains that there’s a carbon compound under the cap that cleans lenses much like the ink in newspaper works to clean glass. It does work. It can be used many times over, as long as every time you put the cap back on and rotate it, to clean and recharge the pad.
This has become my most used cleaning tool, second only to the Giottos Rocket Blaster. And the two complement each other: while the Lenspen works to clean the glass surfaces of the lens and the camera’s lens mount, I use the Rocket to remove dust from the sensor.
[Some users may be more familiar with Nikon’s Lens Pen, which is the same product under a different name. Note the difference in Amazon customer reviews between the Lenspen and Nikon’s rebadged identical twin. –es]