Abstract: A carriage driving mechanism to prevent the carriage adapted to travel as a predetermined wire is taken up from floating and remaining in such floating position due to an unexpected force exerted on said carriage under a tensile force. A carriage support extending from transversely opposite ends is provided with contact arms extending upward, respectively, to come in contact with a top plate of a housing to restrict the carriage from further floating off. Legs directly placed on guide tracks of the housing to support the carriages on the guide tracks and are formed with oil sumps filled with suitable lubricant such as grease. At least one of the legs is formed to adjust a height of this one leg to level the carriage.

Abstract: A lens having a long focal length that is suitable for photography with a large film size is disclosed having three lens groups of positive, negative, and positive refractive power, in order from the object side, as follows: a first lens group having a positive refractive power and formed of, in order from the object side, one or two positive lens element(s), a negative lens element, and a positive lens element; a second lens group having a negative refractive power and formed of, in order from the object side, a negative lens element and a positive lens element; and a third lens group having a positive refractive power and formed of, in order from the object side, a positive lens element, a negative lens element, and a positive lens element. Focusing is performed by moving the second lens group as one unit along the optical axis.