How do I clean the external forward-facing glass on my lens?

Over the last year or so of use it has accumulated a little dust and a translucent smear mark. Nothing serious, but I'd like to remove them nevertheless. The lens in question is a Sigma AF 17-50mm f/2.8 EX DC HSM OS and has a flat external forward-facing glass element (e.g. see here).

I've never cleaned any camera equipment before, so pitch this to a novice audience please.


Assuming you're just talking about the front element - I use these disposable Zeiss wipes. They do better than a lens pen (which handles dust ok, but doesn't do smudges nearly as well) and a box of 200 will last a long, long time with hobby level use. My local Walmart sells the box of 200 for under 4 dollars in the camera and the optometrist section. They won't harm the coatings on the element and do an excellent job.


First use something to blow air across the lens front element to remove the bigger particles, this is important because tiny grains of sand can scratch your lens if you drag them across the lens with a cloth.

A "lens cleaning bulb" thing (not sure how it's called in english) is the best - but use it only in clean environment, you don't want it to fill with dust and blow new dirt on your lens.

You can also use your mouth, but make sure you didn't eat anything recently, especially anything salty.

Than a micro fiber cloth will remove what's left.

If that doesn't work it's time to get lens pen or lens cleaning wipes but the procedure above always worked for me.

  • 1
    Yes, using a bulb to remove particles is an important first step to not scratching the lens. (Giottos Rocket Blowers are great.) However, I would 100% not advocate blowing with your mouth because of the spittle and moisture. In an emergency it's ok, but it should not be the regular course of action. Mar 19 '12 at 12:21

The best thing is to use a Lens Pen specially designed for this purpose. These cost around $10-15 CDN / USD.

The first step is to use the brush side of the pen to remove ALL particles from the lens. Never wipe the lens before brushing as it can drag hard particles which can damage the chemical coatings on the lens.

The second step you use the moist side of the pen to apply a special compound in a circular motion on the lens glass until it looks clean or is not getting any cleaner.

If the lens remains dirty you have to go to a fully wet solution. You can buy optical cleaning fluid, sometimes called ROR (Residual Oil Remover), in a spray bottle from a camera store and even general ones like Walmart. Spray until the lens surface is wet but not soaking. Then wipe with either a microfiber cloth or disposable lens cleaning tissues. These things sometimes come prepackaged in a bundle for under $25 CDN /USD.


I use a Purosol Optical lens cleaning kit, which comes with two bottles of cleaning solution (4-oz and 1-oz) and large and small cloths. I keep the large bottle and cloth at home while I take the small bottle and cloth with me in my camera bag.

It works well, but it does take some practice to avoid streaking. You need to wipe quickly before it dries up to keep streaking to a minimum, and you do need to keep the cloth clean (wash it under water). When used correctly, the solution and cloths can remove virtually all dirt on the lens. In any case, the kit lasts a long time (two to three years for typical use) and costs less than US$25.

I also keep a Giottos AA1900 Rocket-Air blower bulb in my camera bag, and it works well in removing loose dust on the lens.

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