Sometimes device manufacturers provide the ability to drive your application through the web-form on their devices. Samsung, For Example:
From Nokia at the time this happened. Perhaps now is from other vendors.
But in General not a trivial task. If users of Your app a lot, through beta-testing ask them to watch on their devices. However, it is difficult then to clean up their feedback, so it is important to write that check.
Well, if you really need, but does not have one, you can buy the right camera, and the same day to take back to the store. If the unit is rare and in stores not, the question of how much priority on it to test.