Optical system and camera module

An optical system, along an optical axis from an object side to an image side sequentially comprising:

• a first element group, the first element group comprising,
• a first lens, having a positive refractive power, the first lens being configured to converge incident light propagating along a first optical axis,
• a reflective element, configured to redirect the light emitting from the first lens from propagating along the first optical axis to propagating along a second optical axis, the light remaining in a converged state after being reflected by the reflective element;
• and
• a second element group, the second element group having a positive refractive power, the second element group comprising at least one lens arranged sequentially from the object side to the image side along the second optical axis;
• wherein the optical system satisfies:
• 1.7<f1/FG2<2.5, wherein f1 is an effective focal length of the first lens, and FG2 is an effective focal length of the second element group.