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.
USM vs IS. The terms USM and IS are commonly used in camera lenses. Although they are vastly different from each other, there is one thing that is common to them; they both jack up the price of the lenses that have them.