1. Wiping the lens front with your shirt.
What are you, 5?
2. Using compressed air to clean it.
Compressed air is expelled by a propellant, which itself may also eject from the nozzle, damaging the coating on your glass. Instead, try the “air supply” you’ll find in most camera trucks – it’s actually compressed nitrogen, which is moisture-free and won’t react with lens coatings.
3. Touching the front or rear element with your fingers.
Human fluid deposits are corrosive. You guessed it: they’ll also damage lens coatings. Coatings contribute greatly to the quality of a lens – mucking ’em up isn’t in your best interest. Plus, we’ll know it was you. We’ll have your fingerprints.
4. Forgetting to use an optical flat.
You know that stunt where the actress lobs dirt at the camera? Or the one where a car peels out and throws gravel up from its tires? Yeah. Those DPs are using optical flats to protect their lenses. Why? It’s much easier to tell the producer that she has to buy a $300 filter than it is to tell her she owes someone a $35,000 lens.
Don’t be a fool, wrap your . . . Glass. In a filter.
5. Taking it to the beach. Or the desert. Or anywhere with fine debris.
It may feel soft to the touch, but when seen up close (as in the above photo), it’s obvious that sand is incredibly abrasive. Sand and grit can collect inside a lens and cause grinding and sticking in the inner mechanism. Whichever gear house gets that lens back will have to tear it down, re-grease it, and in some cases, replace moving parts inside – rest assured, you won’t get any discounts on your next order.
Because not every shoot takes place in a cleanroom, many ACs carry a soft, white bristled paint brush to dust off the camera and lenses as they’re working. Why white? Most cameras are black, which means that if the brush loses a bristle, it will show up easily against the dark background. If it’s especially windy, using a rain cover (or other means of protecting the camera and lenses from airborne debris) is essential. It seems like a lot of work, but trust us, it’s worth it.
6. Putting it into a wet case (or putting it, wet, into a dry case).
7. Using a high torque focus motor by mistake.
Too much turning force on the focus mechanism can damage internal parts of the lens if the end stops aren’t set correctly.
8. Setting it on the ground.
I could hardly believe it when I heard that we had to replace the front element on three lenses that went out on a one day shoot. It turns out the camera assistant, while swapping lenses, was setting them front-element-down on a concrete floor. Generally, there’s only three places for a lens: on the camera, in someone’s hands, or in the case. And if it can’t be in your hands, it certainly can be the second assistant’s, or the dolly grips’ (yes, grips can hold lenses). In any case, whoever’s holding it should know that while said lens may be worth as much as an Oklahoma cabin (with land), it’s probably a little less durable.
9. Taking it apart in the field.
This sounds really obvious, but it happens. Unless you’re a trained lens technician and have a lens bench and proper tools, it’s very unwise to disassemble a lens on the set.
10. Asking Tiger Woods to aim for the lens.
The $400 filter may have saved the day (see number 4).
11. Letting your little brother use it as a telescope.
He has an excuse. You won’t.