You may know how to use a lens but do you know how they are made? In this post we share some background on lens construction and videos that show the fascinating process.As a filmmaker you are probably very familiar with how to use a lens to capture awesome images. You likely know how they work, but do you know how lenses are made? Knowing how lenses are created isn’t necessary to be a successful filmmaker, but knowing the fundamentals of their construction can help you better understand how they function.Creating a LensIn the simplest terms, a lens is designed to direct light to a camera sensor or film…but that requires much more than a simple piece of glass. Lenses need to be specially optimized to minimize artifacts and chromatic aberrations. Different waves of light react differently with certain glass shapes so careful design is important. While most consumer grade lenses are spherical in design, professional lenses usually utilize an aspheric shape, making them curved instead of fully rounded.Moreover, lenses almost always need to be able to change focus which makes the process much more complicated. Not only do you need more than one piece of glass to change focus, you also need to be able to move that glass back and forth within the lens body. An added iris also creates many more moving parts within a lens body. If the lens is a zoom then there is most assuredly going to be even more complicated moving parts. Most lenses have over 100 parts that must be put on separately.Photo via PhotoReviewThe ProcessAs stated above, there are a lot of different working parts in any lens so there is no simple way to create one. However, in it’s most basic form the process of creating a lens (Nikon) is:Mix glass powder in a large mixerMelt the powder to a liquidSqueeze a large sheet of glass out into a long glass stripCut small measured squares of glass out of the larger stripPlace the squares in a mold and melt in an ovenPolish the glassAssemble the lens body with the glass inside The following video by Nikon shows the process of creating their lenses. Notice how hands-on the lens making process is; definitely an insight into why lenses are so expensive.Bonus Video! How Leica makes their “luxury” lenses.Share your thoughts on lenses in the comments below!