Optical system and optical apparatus having the same

摘要

At least one exemplary embodiment is directed to an optical system which includes a plurality of refractive optical elements arranged substantially symmetrically with respect to an aperture-stop. Furthermore the optical system comprises a refractive optical element being constituted by a solid material. An Abbe number nud of the solid material and a partial dispersion ratio thetagF of the solid material can satisfy the following conditions: thetagF-(-1.665x10^-7.nud³+5.213x10^-5.nud²-5.656x10^-3.nud+0.755)>0, thetagF-(-1.665x10^-7.nud³+5.213x10^-5.nud²-5.656x10^-3.nud+1.011)<0.