Unable to Focus - No Sharp Image

Technical drawing of the 5mm spacer ring

It may not be possible to achieve a sharp image when using a camera with a standard C-mount or CS-mount lens. In most cases, the cause is a missing 5 mm spacer ring, which must be installed between the camera and the lens. This black ring is normally pre-installed on the camera when shipped.

If the protective cap is unscrewed instead of pulled off, the spacer ring may be removed unintentionally. In this case, the flange distance between the lens and the sensor is no longer correct, making proper focus impossible.

It is also possible for a second spacer ring to be installed accidentally during a lens change. In that situation, the camera may only focus at a very short distance, if at all. Removing the extra spacer ring will restore the correct spacing.

Camera, spacer ring, and mounted lens

Camera, spacer ring, and lens separated

Protection cap and spacer ring

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