1. A method for spoof detection for iris based biometric recognition, the method comprising: obtaining a first image of an iris at an imaging apparatus using a first exposure period; obtaining a second image of the iris at the imaging apparatus using a second exposure period; comparing incidence of reflection patterns within the first and second iris images; and determining authenticity of the imaged iris based on a result of comparing the incidence of reflection patterns within the first and second iris images; wherein an imaged iris is determined to be authentic responsive to: (a) the second exposure period being shorter than the first exposure period; (b) the first and second iris images being obtained without varying illumination intensity incident upon the imaged iris; and (c) a reflection imaged within the second iris image having any of (i) smaller size (ii) lower intensity (iii) lower incidence of pixel saturation, (iv) lower incidence of pixel-saturation caused interference with a multi-peak irradiance profile, and (v) higher clarity, when compared to the same reflection detected within the first iris image.