When you see the MS Optics Aporia 24mm mounted on a camera, you'll definitely wonder how they've managed to shoehorn a wide-angle lens into something so thin. Weighing just 45 grams with a thickness that is similar to that of a body cap, the Aporia 24mm is the ideal lens for anyone who wants the most streamlined kit possible. High refractive index low dispersion glass was used for the front and rear lens elements to achieve its ultra-thin profile and you've got a large f/2 aperture with an equally large depth of field. 

$1,100, japancamerahunter.com