The production of a lens is ended by assembly and quality control process. The assembly is not as easy as it seems – it starts with grouping elements together. Then other parts are added, according to appropriate procedure. The quality control is performed during many assembly stages. Unfortunately we couldn't take photos in this part of the assembly hall but we witnessed the fact that the measurements of even isolated groups of elements were rigidly controlled. Lenses are attached to different measuring tools and to cameras in order to take photos of testing charts. What's impressive, these procedures happen already during the assembly.
The final quality control takes place in different rooms where, once again, we couldn't take any photographs. Still, we found out that, in case of new models, every single specimen of a lens is controlled before it leaves the factory. When it comes to older model the control is random.
