Composite optical element and optical system including the same

An optical system comprising:

• a composite optical element including a glass lens and a resin lens that are joined together,
• wherein the resin lens has an aspheric shape, and
• wherein, when Nd is a refractive index of the resin lens, νd is an Abbe number of the resin lens, and θgF is a partial dispersion ratio of the resin lens, the following inequalities are satisfied:
• 1.900<Nd+(0.014×νd)<2.045
• 30.0<νd<35.0
• 0.6200<θgF+(0.0024×νd)<0.6900

An imaging apparatus comprising:

• an optical system;
• and
• an image pickup device that receives an image formed by the optical system,
• wherein the optical system includes:
• a composite optical element including a glass lens and a resin lens that are joined together,
• wherein the resin lens has an aspheric shape, and
• wherein, when Nd is a refractive index of the resin lens, νd is an Abbe number of the resin lens, and θgF is a partial dispersion ratio of the resin lens, the following inequalities are satisfied:
• 1.900<Nd+(0.014×νd)<2.045
• 30.0<νd<35.0
• 0.6200<θgF+(0.0024×νd)<0.6900