For these ultra-wide lenses, the main protection is usually the manufacturer’s cap, which often attaches to the built-in hood. That hood also adds some physical protection against bumps, dust, and splashes.

For transport, treat them like any other premium lens: keep them in a well-padded lens case or camera bag compartment. Since you usually can’t fit a normal UV/clear filter, the cap becomes more important—many photographers keep it on until the moment they shoot, then recap immediately when moving around.

In use, situational awareness matters a lot. With ultra-wides and fisheyes, objects can be closer than they seem, so it’s easy to bump the front element if you’re not careful.

A homemade clear shield can be made from acrylic/plexiglass and taped over the front for special situations, but it has drawbacks: added flare, loss of hood effectiveness, and the need to keep both surfaces dust-free. So it’s more of a niche workaround than a general solution.

In short: use the supplied cap, rely on the integrated hood, carry the lens in a padded case, and be extra careful when shooting.