Many new cameras are sold with a "UV filter" in the bag, and sales staff often say you must put one on every lens. Other photographers say you should never use one. Who is right? The honest answer depends on how and where you shoot. This lesson explains what UV and clear filters actually do on digital cameras, their real advantages and disadvantages, and how to decide for yourself.
What are protection filters?
Protection filters are plain, colorless filters that screw onto the front of a lens. They come in three common kinds:
| Type | What it does |
|---|---|
| UV filter | Blocks some ultraviolet light; mainly used as protection today |
| Clear / protector filter | Plain optical glass with no filtering effect; purely protective |
| Skylight filter | Like a UV filter with a very slight warm tint; a film-era filter |
With film, ultraviolet light could add a blue haze to photos, especially in mountains and near the sea, so UV filters had a real job. Digital sensors are much less sensitive to ultraviolet and already have filters in front of them. So on digital cameras, UV and clear filters do very little to the image. Their main purpose is protection.
The case for using one
- Physical protection: a filter is cheaper to replace than a scratched or cracked front lens element.
- Easy cleaning: sand, sea spray, rain and fingerprints land on the filter, which you can clean freely.
- Harsh environments: beaches, deserts, workshops, crowds, sports events and children's hands.
- Weather sealing: some weather-sealed lenses need a front filter to complete their seal. Check your lens manual.
The case against
- Extra glass: every surface the light passes through can add a little flare and ghosting, especially with bright lights in the frame or at night.
- Cheap filters can lower quality: poor glass or coatings can reduce sharpness and contrast, or add color casts, undoing the quality of a good lens.
- Limited protection: a thin filter may not stop a serious impact; a lens hood often protects the front better from knocks.
- Cost: a high-quality filter for a large lens is not cheap.
Remember:Independent tests by reviewers have generally found that high-quality multi-coated filters make little visible difference in most situations, while cheap filters can cause noticeable flare and softness. The quality of the filter matters more than the decision itself.
Filter or lens hood?
| Protection filter | Lens hood | |
|---|---|---|
| Protects against scratches, dust, spray | Yes | Partly |
| Protects against knocks and bumps | Some | Often better, as it takes the hit first |
| Reduces flare | No; can increase it slightly | Yes, by blocking side light |
| Effect on image quality | None to slight (quality filters); worse with cheap ones | None, or improved contrast |
They are not either-or. Many photographers use a hood at all times and add a protection filter only in harsh conditions. Lens hoods were introduced in optical limitations.
How to decide
- Think about your environment. Sand, salt water, rain, crowds or children: a filter is sensible. Calm, clean conditions: often unnecessary.
- Check your lens. If its manual says a filter completes the weather sealing, use one in bad weather.
- If you use one, buy quality. Choose multi-coated glass from a reputable maker, sized for your lens, with a slim frame for wide lenses.
- Remove it when it hurts the photo. Take it off for night scenes with bright lights, when shooting into the sun, or before adding other filters.
Tip:Avoid stacking a protection filter under a polarizer or ND filter. Extra layers increase flare and can darken the corners of wide lenses. Remove the protector first.
Common mistakes
- Putting a very cheap filter on an expensive lens: it can reduce the quality you paid for.
- Leaving it on for night city shots: bright lights create ghost reflections between filter and lens.
- Thinking it improves color on digital: on modern sensors, the UV effect is minimal.
- Skipping the lens hood: the hood is often the more useful accessory.
What professionals do
Professionals are divided on this, and both choices are reasonable. Some keep high-quality protectors on every lens as insurance, especially for news, events and travel. Others never use them and rely on lens hoods and careful handling. Almost all agree on two points: never use cheap glass, and take the filter off when it causes flare. The decision is a practical one, based on risk, not a rule.
Practical examples
A day at the beach
- Situation
- Wind is blowing sand and sea spray toward your camera.
- What to do
- You attach a quality clear filter and keep the lens hood on.
- Why it works
- Sand and salt can scratch or damage the front element; the filter takes the hit and is easy to clean.
- Result
- The lens stays protected and you can wipe the filter freely.
City lights at night
- Situation
- Your night photos of street lights show small ghost copies of each light.
- What to do
- You remove the protection filter and shoot again.
- Why it works
- Light bouncing between the filter and the lens creates ghost reflections.
- Result
- The ghosts disappear and the lights look clean.
Key points
- UV, clear and skylight filters mainly protect the lens on digital cameras.
- Digital sensors are much less affected by ultraviolet haze than film.
- Quality filters make little visible difference; cheap ones can add flare and softness.
- A lens hood often protects against knocks and reduces flare; the two can be used together.
- Use a protector in harsh conditions, buy quality, and remove it when it causes flare.
Frequently asked questions
Do I need a UV filter for a digital camera?
Does a UV filter reduce image quality?
Is a lens hood better than a UV filter?
Should I leave a UV filter on when using a polarizer?
Conclusion
On digital cameras, UV and clear filters are mainly protective. Use a quality one when your environment puts your lens at risk, rely on the lens hood every day, and remove the filter when it causes flare or before adding other filters. Next, you will learn about the most useful creative filter: the polarizer.
Finished reading? Track your progress through Lenses and filters.