Rotator cuff injuries cause pain in your shoulder and upper arm. The pain may be most noticeable when you reach up or out. When you turn your arm as you lift it, the tendons are more likely to rub against surrounding structures.
The essential difference between the original series of AF Nikkor lenses and all AF lens types introduced subsequently, from the AF-D versions onwards (see below), concerns the compatibility of a particular lens with Nikon's enhanced Matrix metering system known as 3D Matrix metering that was introduced during 1996.
There are two main types of lenses: convex and concave. Convex lenses often get all the credit. They are the type of lens responsible for magnification and are the most common lens used in photography and other common applications. Concave lenses, though, serve an important role as well. A concave lens is any lens that has an inward curve in the middle.