At least one exemplary embodiment is directed to an optical system which includes at least one first refractive optical element, which includes a solid material satisfying the following conditional expression (1), and at least one second refractive optical element, which includes a solid material satisfying the following conditional expression (2): -1.33.times.10.sup.-3.times..upsilon.d+6.7.times.10.sup.-1<.theta.gF (1) -1.63.times.10.sup.-3.times..upsilon.d+6.2.times.10.sup.-1>.theta.- gF (2) where .upsilon.d and .theta.gF indicate the Abbe number and the partial dispersion ratio, respectively.