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If you mean the best camera app, I would suggest ProShot (ProShot | Windows Phone Apps+Games Store (United States)). I haven't tested out many camera apps, but I think this one has a lot of features. You may also try the Camera 360 Sight (Camera 360 won't be upgraded to Windows 10, that's why they came up with Camera 360 Sight). (Camera360 Sight | Windows Phone Apps+Games Store (United States)).
On the other hand, if you meant best camera on a Windows Phone, then Lumia 930 would be the best one.
I think L1020 (Same as Nokia 808) has the best camera in the world for smartphones.