| Problem | Likely cause | Try |
| No autofocus, but DOF preview works | The lens is set to manual focus mode. | For VS28-80 and VS70-200, set the AF/MF switch to AF, and for all other lenses, set the aperture ring to any position other than minimum (f/16, f/22 or f/32 depending on lens). |
| Neither autofocus nor DOF preview | Pin 3 of Contax lens does not make contact. | Check contact between conurus circuit and Contax lens. |
| Camera shows an aperture value of 5.6 | Pin 5 of Contax lens does not make contact. | Check contact between conurus circuit and Contax lens. |
| Camera shows an aperture value of 16 | Pin 6 or pin 9 of Contax lens does not make contact. | Check contact between conurus circuit and Contax lens. |
| Camera shows an aperture value of 7.1 or 6.7 | Pin 7 of Contax lens does not make contact. | Check contact between conurus circuit and Contax lens. |
| Camera shows an aperture value of 8.0 | Pin 8 of Contax lens does not make contact. | Check contact between conurus circuit and Contax lens. |
| Camera shows an aperture value of 1.0 | Pin 1 of Canon camera does not make contact. | Check contact between conurus circuit and Canon camera. |
| Camera shows an aperture value of 0.0 | Camera cannot communicate with conurus circuit | Try the lens on a different camera. |
| Camera displays any other aperture value but you cannot set the aperture value | Camera communicates with conurus circuit, but conurus circuit cannot communicate with Contax N-mount lens. | Inspect whether all pins of conurus circuit make contact with Contax lens connector. |
| Aperture blades make a ticking noise repeatedly | Camera communicates with conurus circuit, but conurus circuit cannot communicate with Contax N-mount lens. | Inspect whether all pins of conurus circuit make contact with Contax lens connector. |
- An error code is displayed on the camera as an aperture value only for mounts shipped after 2006/09/25.
- Not all camera bodies display the error code. Some display "20" or "00" for all errors.
- In some cases, error code may display only if lens is attached while shutter release is half-pressed, or after the shutter-release is half-pressed for more than 2 seconds.
- Contax lens pins are numbered clockwise, with pin 1 of the Contax lens mount being the one which is smaller than the other 9.
- Canon camera pins are numbered counter-clockwise - pins 1 to 3 are raised higher than the other 5 pins on the camera side.
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