From time-to-time (usually only after reinstalling) you may find that your Hipstamatic viewfinder is black/blank/closed. The app needs permission to access the camera on your device.
That setting is easily updated!
Just open the Settings app on your device and look for the following location:
Settings → Privacy → Camera
Just make sure the switch next to Hipstamatic is flipped to “ON”
Then do a safe restart of the app (no need to reinstall) and see if things are working better.
If the instructions in this thread haven't helped, please send us an email to: firstname.lastname@example.org. Provide as much details as you can about the specific situation you're having on your phone/device.