lens cap
lens cover

She walked over, removed the lens cap and looked through it.

All he needed to do was take off the lens cap and set the camera rolling.

For one thing, you can look at it: no lens caps left on there.

I could see why she kept on the lens caps.

A lens cap is good protection but, of course, you can't shoot through it.

With sweating hands, he took off his lens cap and began to shoot photos.

Many people are sure they know the reason that lens caps are black.

Be sure to take the lens cap off before photographing.

Since lens caps are the first thing every photographer loses, it's not a bad idea.

"By putting lens caps on the television cameras until everything blows over," said the King.