The lens device and the vibration-proof adapter include a lock mechanism with operational ease because a lock mechanism of a vibration-proof lens has a switch on a joint with a camera main body or a joint with the lens device. Wavelength \u03bb1 is in the range of 0. The nano-scale dispersion acts as grain boundary pins that result in a relatively fine grained, equiaxed structure that improves the mechanical properties of the alloy and helps to minimize the growth of large grains during operations at high temperatures. The first lens group includes a reflecting optical element that bends the optical path.