A projection system , comprising: a light source configured to emit a light in response to an image data; an illumination optical system configured to steer the light, the illumination optical system including a first mirror and a second mirror ; a digital micromirror device including a plurality of micromirrors , wherein a respective micromirror is configured to reflect the steered light to a filter as on-state light in a case where the respective micromirror is in an on position and to reflect the steered light to a light dump as off-state light in a case where the respective micromirror is in an off position, the projection system comprising the filter , wherein the filter includes an aperture ; and a controller configured to: determine a deviation between an actual angle of orientation of the digital micromirror device and an expected angle of orientation of the digital micromirror device, calculate a first amount of angle adjustment corresponding to the first mirror and a second amount of angle adjustment corresponding to the second mirror, and actuate the first mirror according to the first amount and the second mirror according to the second amount, thereby to maintain a position and a focus of the steered light on the digital micromirror device and to cause the on-state light to be incident within a predetermined distance from a center of the filter. a light source configured to emit a light in response to an image data; an illumination optical system configured to steer the light, the illumination optical system including a first mirror and a second mirror ; a digital micromirror device including a plurality of micromirrors , wherein a respective micromirror is configured to reflect the steered light to a filter as on-state light in a case where the respective micromirror is in an on position and to reflect the steered light to a light dump as off-state light in a case where the respective micromirror is in an off position, the projection system comprising the filter , wherein the filter includes an aperture ; and a controller configured to: determine a deviation between an actual angle of orientation of the digital micromirror device and an expected angle of orientation of the digital micromirror device, calculate a first amount of angle adjustment corresponding to the first mirror and a second amount of angle adjustment corresponding to the second mirror, and actuate the first mirror according to the first amount and the second mirror according to the second amount, thereby to maintain a position and a focus of the steered light on the digital micromirror device and to cause the on-state light to be incident within a predetermined distance from a center of the filter. determine a deviation between an actual angle of orientation of the digital micromirror device and an expected angle of orientation of the digital micromirror device, calculate a first amount of angle adjustment corresponding to the first mirror and a second amount of angle adjustment corresponding to the second mirror, and actuate the first mirror according to the first amount and the second mirror according to the second amount, thereby to maintain a position and a focus of the steered light on the digital micromirror device and to cause the on-state light to be incident within a predetermined distance from a center of the filter. <EOS>