Perspective correction

You can get perspective correction, or ‘shift’ lenses, but perspective correction is easier to carry out in software these days. You use it to correct converging verticals, or ‘keystoning’, in photographs of tall buildings where you’ve had to tip the camera upwards, but you can also correct horizontal convergence or both at the same time – for example if you are photographing flat artwork and you can’t shoot from a perfectly perpendicular position.