If your time clock's face capture screen is gray, it means that your Apple settings are blocking Fareclock access to the device camera. Particularly, this might happen in iOS 8 when Apple started prompting the user to allow permission. If you select No to this prompt, then Apple blocks camera access to Fareclock.
To correct this, go to your device's home screen, and open the Settings app. You should see this:
Next scroll down to the app list, and select Fareclock:
After selecting Fareclock, you should see this:
Next, select Privacy:
From there, make sure Camera is enabled. If it is enabled, then the slider icon should be green.
That's it! Now go back to the Home Screen, and start Fareclock app again. The face capture screen should be normal.