vanishing bubble

Exposure Date: 2012:07:28 16:40:29;
Make: Canon;
Model: Canon EOS 7D;
ExposureTime: 1/1250 s;
FNumber: f/1.8;
ISOSpeedRatings: 200;
ExposureBiasValue: 0;
Flash: Flash did not fire, compulsory flash mode;
FocalLength: 50 mm;
Software: Adobe Photoshop CS4 Windows;