If you were to only read about his antics, Norbert Wittekindt might appear like some kind of psychopath. He takes top-end Carl Zeiss lenses and drops them onto hard floors. Not only that, he freezes them and then brings them into warm rooms and clamps them onto machines which try to shake the lenses apart. What’s going on?
Norbert , you may have guessed, is a professional stress-tester, and puts the pressure not just on Zeiss lenses but also medical tripods and other important gear. The temperature test sees a poor lens heated to 70˚C for several hours, then dropped to -40˚C, taken up to -20˚C and then heated again, up to 55˚C.
This double-teams the lens. Not only are the metal and glass expanding and contracting at different rates, but the seals are extra important to stop condensation forming permanently inside the lens.
Next up is the vibration test, putting five to ten years’ worth of transportation wear onto the lens in a few minutes. If Norbert wasn’t so sternly professional, you’d half expect him to start an impromptu game of football in the lab, using, say, a fisheye lens as a ball.
The video is fascinating, and shows you why high-end pro lenses cost so much. It also shows you why, once you have paid the money, these lenses should last you forever.