Systems and methods for use with a handheld mark reader that reduce the time between activation of the reader's trigger and the reader returning a successful decode response. Image processing may be performed prior to the user actuating the trigger and thus obtaining a decodable image with reduced delay. Separate pre-trigger and post-trigger parameters may be used for image decoding. A feedback loop may be incorporated for repeated parameter updates. An adjustable lens may be utilized either with illumination OFF or ON.