How To Clean A Filter

A dusty or fingerprint covered filter will produce shots that are either dotted with annoying specks or ones that aren't sharp. As neither outcome is something you'll want, it's worth checking your filters so, if needs be, they can be cleaned. Cleaning a filter isn't something you'll need a Phd in physics to be able to complete successfully, but there are a few tools and techniques you can use to ensure your filters are squeaky-clean. 

Useful Tools

• Air blower
• Lens brush
• Lens cloth (microfibre)
• Disposable lens tissues
• Lens cleaning liquid

Cleaning Process

1.  Check the filter before using a cloth on it as you don't want to rub grit against the filter as this could scratch it. Instead, use an air blower to remove the debris or a soft brush to gently brush the surface.

2. For smudges and fingerprints, take a lens tissue, fold it once or twice (depending on size), and place a couple drops of liquid lens cleaner on the tissue (never directly onto the filter's surface) and wipe with the tissue in a circular pattern starting from the center and moving out to the edge.

Some use a micro fibre lens cloth for this however, HOYA doesn't recommend you using a standard fabric lens cleaning cloth with any liquid because dust can become trapped in the fibers and damage the lens or filter on subsequent uses. If you're not using a cleaning liquid, it'll be fine to use a lens cloth for cleaning your filter but stay away from coarse materials such as paper towels. 

3. Immediately follow the first tissue with a new dry tissue using the same pattern or if the surface is free from dust, you can use a lens cloth if you prefer but ideally, you should use a second disposable lens tissue as you can guarantee this will be grease- and dust-free.