Friday, 2 March 2018

This is the Result of Placing My Camera Lens 300 Feet from a Rocket Launch

My name is John Kraus, and I work as a photojournalist at Cape Canaveral, covering rocket launches with up-close cameras at the various launchpads here. For yesterday’s Atlas V rocket launch, I had two cameras at Space Launch Complex 41. These cameras were sound-activated; the sound alone would kill anyone standing at the launchpad during liftoff.

Both remote cameras I placed were Nikon D7000s, but each was poised to shoot drastically different images. Both cameras and their lenses were wrapped in plastic grocery bags, with a hole cut out for the front element to poke through. At a relatively safe distance from the rocket — maybe 500 or 600 feet — one D7000 was equipped with a Nikon 80-200mm f/2.8 and was zoomed in to capture a closeup shot of the rocket’s engine and four solid rocket boosters.

That setup was completely unharmed. This post will focus on the other camera setup.

The other D7000, which was just over 300 feet away from the rocket, was in the midst of the chaos. This camera was armed with an 8mm Rokinon fisheye lens that I picked up the day before remote camera setup. This camera was just to the left of the flame trench, of which is where most of the rocket’s energy is directed.

Here’s my favorite image from the fisheye setup:

The afternoon backlighting was great. I’m really pleased with the resulting images. According to my in-camera time, the above image was taken at 15 seconds past the minute.

Here’s a photo from :20, five seconds after that image:

And here’s :26, 11 seconds after the first image:

This image is why I think there was a mixture of both water and solid exhaust on my lens.

The Aerojet Rocketdyne AJ-60A solid rocket motors used on this rocket are fueled by hydroxyl-terminated polybutadiene, which is very acidic. We were warned by our NASA escort to not touch our faces after handling equipment coated in the solid rocket exhaust and to wash our hands ASAP after arriving back at the KSC Press Site.

Here’s a photo of what the lens looked like right after I picked it up from the launchpad:

The residue is a sort of dried, cake-y, powdered material stuck to the lens. I’m guessing that the solid exhaust mixed with the water from the pad’s water suppression system, and that resulting substance adhered to the lens.

After I got home, I took a wet cloth and wiped off the powdery substance. It came off relatively easily, and I initially thought the lens was fine after I dried it off. That was until I looked at it in better light. The lens was heavily pitted from the solid exhaust particles.

That’s not sand or dirt resting on the glass — that’s pitting in the front element itself. Note the dirt and twigs around the glass, too.

I’d likely be able to replace just the front element, but I picked up this lens for a hundred bucks, so if I want to do a fisheye shot for a future launch, I’ll probably just buy another one. I’ve retired this lens after just one launch. The same thing happened to an 18-55mm kit lens I placed next to a Delta IV launch in 2016.

Looking through the viewfinder of a body with that lens mounted is like looking through glass covered in raindrops.

Now, I have some explaining to do, because inevitably, someone is going to write “WHY DIDN’T YOU JUST USE A UV FILTER!?!?!?” in the comments below.

Using a glass filter triples the area that dew can form prior to liftoff. I’ve had shots ruined by dew forming on the front element. Add in a filter, and you’ve got the front element and two additional glass surfaces for dew to ruin your shot. Cheap filters can introduce unwanted image artifacts such as glare. And why use quality filters if the same thing can happen to them rather than the front element?

And yes, I only use plastic grocery bags to protect the cameras. Both the camera bodies were fine. It was just the exposed fisheye lens that saw damage. Overall, I’m really happy with my resulting images from both setups, so I’m not bummed at the loss of the fisheye lens.


About the author: John Kraus is an 18-year-old photographer based in Florida. He shoots a wide variety of subjects including rocket launches, landscapes, aerial photography, astrophotography, aviation, and much more around Florida. You can find more of his work on his website and Instagram.



from PetaPixel https://petapixel.com/2018/03/02/result-placing-camera-lens-300-feet-rocket-launch/

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