Lens coatings are thin layers applied to glass surfaces to control reflections. Without them, a lens with many glass elements would lose light and show flare, ghost images and washed-out contrast. Coatings are the reason modern lenses can use complex designs and still give clear, contrasty pictures.
Why Reflections Are a Problem
Every time light passes from air into glass, a small fraction reflects. A lens with a dozen or more elements has many such surfaces. The reflected light bounces around inside the lens and can reach the sensor as veiling haze, bright spots or coloured shapes, especially when you shoot toward a strong light source.
Common Types of Coating
- Anti-reflective coatings: thin layers that cancel out reflections by wave interference, often applied in several layers.
- Multi-coating: multiple anti-reflective layers, tuned for different wavelengths of light.
- Nano-structure coatings: makers use special surface structures to cut reflections further, especially on curved elements.
- Front-surface coatings: a hard or water- and oil-repellent layer on the outer glass that helps with cleaning.
Brand names differ, so read the maker’s description to learn what a particular label covers.
What You May Notice in Photos
Better coating control tends to give higher contrast, richer colour and fewer flare artifacts when light hits the lens at an angle. Even so, no coating removes flare completely. A lens hood still helps by blocking stray light before it enters the front glass.
Flare and Ghosting Compared
Flare appears as a hazy veil or streaks that lower contrast. Ghosting appears as repeated bright shapes, often matching the aperture blade outline, caused by reflections between lens surfaces. Both are more likely when a bright light sits near the edge of the frame, and some photographers use them deliberately for a dreamy look.
Coating Habits and Care
- Use a lens hood to cut stray light and give some physical protection.
- Remove dust with a blower before you wipe anything.
- Use a clean microfibre cloth and a cleaner made for lenses, applying liquid to the cloth and not the glass.
- Wipe gently in a circular motion from the centre outward.
- Avoid household cleaners and rough tissues, which can mark coatings.
- Follow the maker’s cleaning advice for your specific lens.
Where Coatings Matter Most
| Situation | Why coatings matter |
|---|---|
| Shooting toward the sun | Reduces flare and ghosts |
| Night street scenes with lamps | Limits ghost images near lights |
| Zoom lenses with many elements | Preserves contrast across the range |
| Shooting in rain or spray | Easier cleaning with repellent layers |
FAQ
Does a filter on the front affect coatings?
A filter adds two more surfaces. A good coated filter has little effect, but a poor one can add flare. Many photographers remove it for backlit scenes.
Can coatings wear off?
They can be damaged by abrasive cleaning or harsh chemicals. Gentle care keeps them in good condition for years.
The Short Version
Coatings reduce reflections, so lenses give clearer, more contrasty images. Use a hood, clean gently, and read the maker’s description for the specific type of coating on your lens.
