The cameras were manufactured by the Itek Corporation. A , f/5 triplet lens was designed for the cameras. Each lens was in diameter. They were quite similar to the Tessar lenses developed in Germany by Carl Zeiss AG. The cameras themselves were initially long, but later extended to in length. Beginning with the KH-4 satellites, these lenses were replaced with Petzval f/3.5 lens. The lenses were panoramic, and moved through a 70° arc perpendicular to the direction of the orbit. A panoramic lens was chosen because it could obtain a wider image. Although the best resolution was only obtained in the center of the image, this could be overcome by having the camera sweep automatically ("reciprocate") back and forth across 70° of arc. The lens on the camera was constantly rotating, to counteract the blurring effect of the satellite moving over the planet.