Today in optics part we will talk about very compact wide angle photo lens Olympus Body Cap Lens 15mm F8 for Micro Four Thirds mounts ( for Panasonic and Olympus cameras ). Its 15 mm focus is fixed ( 30 mm in full-frame equivalent, taking into account sensor crop-factor 2 ), focusing is performed by lever on its body from 0.3 m to infinity; it has no support for automatic focusing and diaphragm settings and lens does not communicate with camera in any way. Diaphragm is fixed at f/8 point; magnification is 0.06x; 3 lens elements in 3 groups are built into it. Olympus Body Cap Lens 15mm F8 sizes are 9 ( length ) x 56 ( diameter ) mm and mass is 22 g. Package contains : Olympus Body Cap Lens 15mm F8 lens itself, rear cap and user’s guide. From one side : it is very compact and has wide field of view; from the other : it has weak image quality ( lots of vignetting ( brightness decrease to frame sides ) and noticeable chromatic aberrations increase to the sides of image ), so, this lens has little practical meaning and is mostly spending money on the wind and it is better to buy wide angle converter lens for existing photo lenses and receive much better image quality and exposure control for the same or even smaller price.