We interrupt this blog for a photo public service announcement (PSA).
I was on day three of a four day conference I was documenting. We’d just come down from the Mount of Olives, and I was cooling off before dinner. I was also getting my photo gear ready for the evening session.
So I take out the camera with the telephoto lens out of the backpack and go to put the hood on when I see this:
After a moment of panic, I see that only the front glass is cracked. Why did that console me? Because it was only the UV filter.
Most lenses have an inner thread on the front so that you can attach filters that enhance color or contrast or add a special effect. But we add most of those enhancements with Photoshop or other software these days.
The UV filter, as it says on the back of my replacement filter’s box, “absorbs UVB and UVC rays to give clearer and sharper pictures with less haze.” Here’s the really important part: “Constant use for lens protection is recommended.”
See-through lens cap
When I started my first photojournalism internship as I changed from copy editor to photographer, I asked the photo editor at the Idaho Falls Post-Register if there were lens caps for the lenses. He laughed a hardy laugh.
The UV filter is your see-through lens cap. It protects the front element of your lens from dust and scratches. The UV filter is the piece of glass you’re not afraid to clean with a bit of spit and your shirt edge in a pinch.
It is also a sacrificial piece of glass that is likely to break should the lens get knocked. Instead of hundreds or even thousands of dollars to repair or replace a camera lens, a UV filter can cost anywhere between $10 to $100 (depending on brand, size and glass quality).
At the camera shop where I bought the replacement, they tried to sell me the more expensive filter. I asked them for the most inexpensive one. “They’re made to be broken,” I said.
In case you are wondering, I shot the rest of the conference with the cracked filter. I was shooting the telephoto at f/2.8 and f/4. The depth of field is so shallow that the camera sees past the crack to what you focus on.
It’s the same concept as shooting (particularly sports) through a fence. If your depth of field is shallow enough, the camera doesn’t see the fence when you focus on what’s beyond it. This is best done with a telephoto lens at f/4 and faster.