Usually, a lens hood is the first thing to use. It helps protect the front of the lens from bumps and also reduces flare, so it preserves image quality better than adding extra glass.

A UV/clear protective filter can add another layer of protection, especially against spray, salt water, sand, mud, and other debris. It can also be easier to clean or replace a filter than risk scrubbing the front element in the field.

The trade-off is that any filter adds another glass surface, which can increase reflections or slightly reduce image quality, especially with lower-quality filters. A good multi-coated UV or clear/NC filter minimizes this risk, but it does not eliminate it completely.

Practical rule: use the hood all the time, and add a protective filter when conditions are harsh or messy—such as beaches, sea spray, blowing sand, or mud. In normal shooting, many photographers prefer the hood alone.