What Exactly is an Aspherical Lense.?

The previous answer is correct. The surface of 'ordinary' lenses trace the contour of perfect spheres. With a-spherical lenses, the surface of one or more glass elements doesn't. I have a 50mm Nikon f/1.4, and the front element looks like it has a big dimple in it. That's aspherical. As stated, the aspherical elements are there to correct for distortions. If anything, these lenses are more complex and more expensive to make.

The word means "not round" and in eyeglasses, it means its the more expensive version of reading glasses; presumably because its magnification makes the letters up close more similar in size to those further away, thus taking care of that BIG NOSE problem you might have with a fish eye lense, or what we might see when we look in a convex mirror. So, it does the magification different on the perimeter than in the middle. It's a GOOD thing.

Aspherical lenses is for people who have astigmatism.

You need to know what your prescriptions are to buy them anyway.

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