Ground Glass is glass whose surface has been ground to produce a flat, matte finish. A sheet of ground glass is used for the manual focusing of both still and motion picture cameras.

The ground glass element in the Letus35 adapters is a flat translucent material that is electronically vibrated back and forth very rapidly. This element is what the SLR lens attached to the end of the adpater projects upon so the image sensors inside the camera can see what the SLR lens is seeing.

Two AA batteries power the components that move the ground glass element in the Letus adapters. The motion is random and very rapid so the camera does not see any of the texture on the glass. Should one turn off the vibration unit, a fine grain would be visible on screen. This is how the ground glass appears when it is not moving. Once the electronic unit is turned back on, the ground glass "dissapears" to the camera leaving only the reflected image coming from the SLR lens.

Normally the image on the ground glass would appear upside down but with our Flip and XL/HD series of adapters, we use a series of mirros to right the image so the camera previews and records just as it would normally. This is an incredibly helpful feature as it removes the need to rig up awkward previewing screens to see the image correctly. The image is also recorded up-right so there is no need to alter the footage in post production to view it properly.