Was This on My Lens!?

January 20, 2012

Jetcontrail by jensloeffel01

Photographer: Jens Hackmann
Summary Author: Jens Hackmann; Jim Foster

Have you ever looked at a picture you've taken and wondered "How in the world did THAT thing get on my lens?" In this case, the "thing" isn't a turbo-charged worm of some kind but rather an eye-catching jet condensation trail (contrail). While capturing images of the sunrise over southern Germany about 8:10 January 3, 2012, I couldn't help but notice this odd appearing contrail flying towards the Sun – off the lower left-side of the photo. Contrails take shape when hot, moist air from jet exhaust mixes with the cold ambient air, having a lower vapor pressure than the exhaust gases. As the exhaust gases cool, they condense into an artificial cloud composed of minute water droplets or ice crystals.

This contrail and the cirrus deck above the eastern horizon are sufficiently high, over 30,000 ft (9,150 m), to reflect the dawn’s early light. Wind shear to the rear of the jet is responsible for the kink in the contrail. Further behind the jet (top and top center of photo), atmospheric turbulence gives the trail its loopy look.

Photo details: Camera Maker: Canon; Camera Model: Canon EOS 5D Mark II; Lens: EF100-400mm f/4.5-5.6L IS USM; Focal Length: 400.0mm; Focus Distance: 4294967295.00m; Aperture: f/9.0; Exposure Time: 0.0063 s (1/160); ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; Exposure: Manual; Exposure Mode: Manual; White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB; Software: Adobe Photoshop Camera Raw 6.6 (Windows).