Low Magnification Video Lenses

Dyotar lenses from Navitar were designed to provide superior performance over standard C-mount video lenses for close-up imaging. They have been optically corrected for remarkable image quality and high depth of field. As a direct result of this correction, aberrations (particularly field curvature and distortion) are minimal.

Designed and developed for large formats, Dyotar lenses provide accurate imaging on large linear detector arrays and unparalleled quality on the smaller video formats. The resolution capability (the ability to distinguish minute detail) far exceeds that of even a high-resolution video camera. Dyotar lenses produce a flat field with low distortion. Aperture control permits increased depth of field.

All Dyotar lenses are available with a C-mount adapter (3-6065) which provides a convenient and secure means for attaching the lenses to a standard video C-mount camera. A complete spacer kit (540E) is available along with 50 mm (3-6072) and 100 mm (3-6071) extensions that space the lens from the camera.

Dyotar lenses are supplied with a high quality, broadband, high efficiency, anti-reflection coating that has been optimized for best performance in visible light.

Selecting the Correct Lens

Simply choose the block from the "Dyotar Operating Parameters Chart" on the following page that most closely approximates your requirements. Read the lens and spacers from the margins. Please note that the 18 mm adapter must be subtracted from the spacer value in order to arrive at the correct extension tube length.

Object size  = 1" square  (25.4 mm x 25.4 mm)
Camera format  = 2/3"
Working Distance  = Must be at least 12" (304.8 mm)

First, calculate the required magnification. The camera sensor is 8.8 mm x 6.6 mm. Therefore, the vertical imitation of 6.6 mm determines the required magnification. To image 25.4 mm onto 6.6 mm, a reduction of 6.6/25.4 = 0.26X is required. When rounding the final figure, opt for the next highest size available.

The chart indicates that the DY-75TL lens will produce .25X at a 362 mm working distance. The spacer required is 70 mm total or 52 mm in addition to the 18 mm adapter. Since somewhat more than .25X is desired, the spacer must be no longer than 52 mm. Assume a value of 62 mm. The proper spacer is fabricated by selecting a 40, 20 and 2 mm from the kit. At this point, only minor adjustments to the spacer will be necessary to complete the set up.

Dyotar Lenses - Operating Parameters Chart