Spring Lake, MI. Sponsored Topics. Spring Lake is a village in Ottawa County in the U.S. state of Michigan. The population was 2,514 at the 2000 census. The village is located within Spring Lake Township. After Captain Benjamin Hopkins purchased land here in 1837 and built a mill, the place became known as Hopkins Mill.
All binoculars will have two numbers to designate them, such as 10x50. This means a binocular with 10 times magnification and 50mm objective lenses (the big ones!). Common sizes are 8x42, 10x50, 20x60, 15x70, etc. Optical glass is generally BAK4 or BAK7 standard, BAK4 is denser and gives superior vision.
The First Number: Sphere. Here is a basic lens prescription for someone who is nearsighted. First thing first, OD means right eye. OD is an acronym for a latin phrase that no one cares to remember. The sphere in this case is -1.25 for the right eye, and -1.50 for the left eye. There is an important point to be made. Regardless of if there is a + or - before the sphere number, the rule of thumb is, the higher the number, the worse the eyesight.