Douglas,
Fully coated refers to a lens being coated with a single layer of metal oxide coating. The "fully" part refers to the entire lens surface.
"Multicoated" means multiple layers of coatings.
"Fully multi coated" can refer to one lens or all lenses on the device - which should be the case.
Virtually all modern optics are at least multicoated, for good quality chose fully multicoated.
the 50mm or 50 after a number and "x" refers to the objective (front) lens size, and is the most important "hard" spec; it will dictate how much light can enter your binos and eyes, and how big and heavy the tool will be.
The most important factor in optics is quality, optical quality and build quality, which is difficult to quantify so you need to test personally or rely on reviews and reputation.
Fully coated refers to a lens being coated with a single layer of metal oxide coating. The "fully" part refers to the entire lens surface.
"Multicoated" means multiple layers of coatings.
"Fully multi coated" can refer to one lens or all lenses on the device - which should be the case.
Virtually all modern optics are at least multicoated, for good quality chose fully multicoated.
the 50mm or 50 after a number and "x" refers to the objective (front) lens size, and is the most important "hard" spec; it will dictate how much light can enter your binos and eyes, and how big and heavy the tool will be.
The most important factor in optics is quality, optical quality and build quality, which is difficult to quantify so you need to test personally or rely on reviews and reputation.