Imaging lens system and camera

A camera comprising:

• an imaging lens system that forms an optical image of an object;
• and
• an imaging device that converts the optical image formed by the imaging lens system into an electrical image signal,
• wherein the imaging lens system includes, in order from an object side to an image side,
• a first lens group consisting of at least one lens element having negative power,
• a second lens group having positive power and configured with a single lens element, and
• a third lens group having power,
• the third lens group includes a lens element having positive power and a lens element having negative power,
• a lens element closest to the object side in the first lens group is a negative meniscus lens having a convex surface on the object side, and
• conditional expressions (1), (2), (4), and (7) shown below are simultaneously satisfied,
• −1.2×10−5<dn/dtpi<0, where i≥1 (1)
• −1.0×10−6<dn/dtmi<1.5×10−5, where i≥1 (2)
• −0.2<f/f12<1.5 (4)
• ν3mi<35, where i≥1 (7)
• where
• dn/dtpi is a relative refractive index temperature coefficient of an i-th lens element having positive power included in an entire system for light in a wavelength range from 580 nm to 640 nm, inclusive, in air in a range from 0° C. to 20° C., inclusive,
• dn/dtmi is a relative refractive index temperature coefficient of an i-th lens element having negative power included in the entire system for light in a wavelength range from 580 nm to 640 nm, inclusive, in air in a range from 0° C. to 20° C., inclusive,
• f is a focal length of the entire system at a d-line,
• f12 is a composite focal length of the first lens group and the second lens group at the d-line, and
• ν3mi is an Abbe number at the d-line of an i-th lens element having negative power included in the third lens group.