Saw the movie on TV around 1975 to 1980 in Germany (likely dubbed from another language), could be color or b/w. Most TVs back in that day were b/w.
I only remember scenes where a small group of people (5?) were on a remote island, and for some reason wanted to get on top of a hill.
When they approached and tried to walk up the hill, devices were raised from the ground that then shot some kind of energy at the people, which made them retreat. One guy then devised a kind of “lightning rod” contraption (made of wood and metal?) that they would carry (like a backpack?) to deflect the energy emitted by the devices. It worked and they finally made it past the devices to find… something or someone.