The diffrence between thick and thin lens depends on your precription for your eyes.
In optics, a thin lens is a lens with a thickness (distance along the optical axis between the two surfaces of the lens) that is negligible compared to the focal length of the lens. Lenses whose thickness is not negligible are sometimes called thick lenses.
convex lens
A convex lens.
The focal length of a lens is the distance from the principal foci to the center of the lens.
converging lens show virtual and real images while diverging shows virtual images.
In optics, a thin lens is a lens with a thickness (distance along the optical axis between the two surfaces of the lens) that is negligible compared to the focal length of the lens. Lenses whose thickness is not negligible are sometimes called thick lenses.
There is no difference between lense and lens. All is the same.
There is none
the name
The lens size is the only difference the XL have a bigger lens.
one is single lens and the other is multi lens
A convex lens.
convex lens
It's about a $300-400 USD price difference.
The focal length of a lens is the distance from the principal foci to the center of the lens.
converging lens show virtual and real images while diverging shows virtual images.
the ocular lens sits higher up, closer to your eye. the objective lens are in the objective tube below the ocular lens