The idea is that you shoot through the viewfinder of an old camera using your modern digital or film camera and create an interesting framing effect. 

The TtV Camera can simulate the old camera’s viewfinders and you can shot photos with those amazing effects.
 This app usually retails for $2.99/£1.99 but today you can pick it up for only $0.99/£0.69, just click here to do so.