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A critical skill for photographers to learn is how to clean camera lenses. No matter how hard you try, your gear is going to get dirty if you are out taking pictures. Even if a lens doesn’t leave your bag, dust is inevitable. The point is, you need to be able to clean your lenses and do it the correct way.
Luckily, it is not that difficult. You can safely clean any lens even when you are out in the field. We are going to look at how to clean the lens and what you should have on hand.
Why Lenses Must Be Cleaned Correctly
While most lenses are reasonably durable, glass can and will scratch. Foreign material from a dirty cloth, for example, can scratch your lenses while you are trying to clean off a smudge. So what you use to wipe a lens needs to be very clean.
More delicate than the actual glass itself is the coatings that are applied to the front and rear elements. These coatings can do everything from protecting the lens and camera from UV light to reducing glare and many other functions. Certain chemicals and abrasive cleaning can damage these coatings.
Additionally, the coatings can react with certain types of cleaners and leave streaks or cloudy films on the glass. Acetone is one chemical that should never be used to clean a lens.
Only Clean When Necessary
One of the first tips about cleaning your lenses is “Don’t.”
In other words, unless you truly need to clean them, you should avoid it. The reason for this goes back to the fact that the glass and coatings can be damaged and degraded over time. Every time that you clean your lens, you are affecting its overall quality and life expectancy.
Now, this is not to say that a quality lens can’t withstand hundreds of cleaning and still produce high-quality photos; it can. However, those of us that would like for our lenses to serve long lives would benefit from cleaning as less frequently as possible.
Most debris that gets on the front element can be brushed away with a soft bristle brush without any chemical or “wet” cleaning needed. Most photographers prefer camel or goat hair brushes for this task, and this should be one of the tools you carry in your camera bag. Personally, if I can outside and stepping away from my bag, my lens brush is one item I will stick in my pocket.
The stuff that you can’t brush away is generally going to be oily smudges or fingerprints. In most cases, this will require a cleaner to act as a solvent to remove from the glass.
Another popular and useful tool for lens cleaning is an air blower. These handheld bulbs produce a puff of air when you squeeze them. They will generally have a nozzle at one end so that you can aim the airflow at specific parts of the camera. A quality blower can be a convenient device to have in your kit.
Even though blowing air is an acceptable way of clearing debris from an element, you should never use a can of compressed air. Pressurized dust cleaner produces too much force when sprayed, which can damage parts of your camera and lens. The excessive pressure can also stir up more dirt into the air and actually make the situation worse.
Additionally, the “canned air” products do not actually contain what we would call “air,” but are generally made from compressed gases such as difluoroethane, trifluoroethane, tetrafluoroethane, or butane. These gasses can react with the coatings on your lens, and the fumes can damage your camera. They should be avoided.
How to Correctly Clean a Lens
Step 1: Use Soft Brush
Remove all of the dust and debris as possible with a soft bristle brush. It is important to make sure the brush is clean and free from oils or other particles.
Step 2: Apply Cleaning Solution
Apply a few drops of cleaning solution to a fresh lens wipe or clean microfiber cloth. Most companies have their own cleaning solution, but any solution that is designed for lens cleaning should be fine. Make sure you read to make sure that it is safe for your specific lens coating before using.
Step 3: Wipe
Clean with just enough pressure to remove the dirt, starting from the outer edges and moving inwards in a circular pattern. Going from the center out can “push” dirt and debris into the edges of the lens where the body meets the element, and can make it harder to remove.
This technique can be done to the front element or rear element of the lens. It also works well for either side of an optical filter.
What To Do With Dust Inside A Lens
Every photographer has a moment when they look into a lens and see dust inside and immediately go into panic mode. Our lenses are the most critical part of our camera after all, and the dust must be affecting image quality!
The truth is, dust inside a lens is entirely normal. While very high amounts of dust can be a problem, generally it is benign. Even a brand new lens fresh from the factory will have some dust particles inside. The reason for this is that the lens body is not airtight. In fact, it “breathes” when you zoom in or out or adjust the focus ring. As the elements move inside, air rushes into and out of the lens body. If not, the air pressure would make it impossible to adjust the lens more than a tiny amount. This air movement is what cause dust to enter your lens.
We can certainly reduce the amount of dust that gets into our gear by cleaning properly and storing our lenses capped and put away in a sealed bag or box. One thing that is often overlooked is cleaning the inside of your gear bag. Removing everything from your bag and vacuuming it out can reduce dust and dirt coming in contact with your gear.
So what can you do about dust inside your lens? Honestly not much.
Some companies do offer a service where you can send in a lens and get it cleaned and refurbished. However, this comes with a significant price tag, and it is generally more cost-efficient to replace the lens instead.
Under no circumstances should you open your lens and try to clean it yourself. First of all, it will void any warranty. Second, you will most likely not be able to reassemble the lens correctly, as it requires an exact measuring of distances between the elements. Third, unless you have a very advanced cleanroom set-up, you would probably get more dust in the lens than you got out.
The good news is that the dust will not affect image quality. The only dust that will show up in your images is dust on the sensor. Dust on the sensor would need to be removed, but it is a completely different topic we are going to address in another article.
So in conclusion, try not to clean your lenses unless it is genuinely needed. If small amounts of debris get on the front or rear element, you can brush it off with a soft bristle brush or a blower. If you do need to clean the lens, make sure that you are using the proper tools, and do it the correct way.
Dust on the inside of the lens is normal, and it will not affect image quality unless it becomes extreme. You can try to reduce the amount of dust that gets into your gear by keeping it sealed up when not in use and cleaning regularly. Do not try and remove dirt or clean the inside of a lens yourself, and never take the lens apart.