If you're not sure, I would start there. iPhones can't seem to delete cache and data like Androids. You have to kill the app in order to MAYBE delete memory from my understanding. You could check within the app to see if there is an option, you could also see if your camera has an update, but I'm just reaching by saying that.
If an app is unresponsive and your iPhone, iPad, or iPod touch still reacts to button presses, you can force the app to close:
I can kill the app any time. However the freeze is on taking new pics. I have just killed all apps and rebooted. Brought the camera up and it was frozen to take pics.
You talk about a cache. Where are the settings to clear that for the camera?