Double-Convex Lens, also named Bi-Convex Lens, is most suitable where the object and image are on opposite sides of the lens and the ratio of the image and object (conjugate ratio) distances is between 0.2 to 5. It is used in beam expanders,. Projection optics systems, optical viewers etc. Specification of our wide angle lens as follow: 25mm 0.45X wide angle lens 27mm 0.45X wide angle lens 28mm 0.45X wide angle lens 30mm,30.5mm,34mm,37mm,43mm,46mm,49mm,52mm,55mm,58mm,62mm,72mm 0.45X wide angle lens Specification of our fisheye lens as follow: *37mm 0.42X fisheye lens; *72mm,82mm 0.7X fisheye lens