Most new cameras have a ‘miniature’ mode, and most image-editing software now offers a tilt/shift filter that will help give the impression that you are Gulliver looking down on Lilliput.
However, these options typically work by blurring the top and bottom of the frame, whereas a genuine tilt-and-shift lens actually shifts the plane of focus.
‘Freelensing’ bridges the gap between these two options by allowing you to change the plane of focus but without paying for a tilt/shift lens.
The principle is simple: set your camera to manual and hold your lens in front of the lens mount, rather than attaching it to the camera.
Turning and tilting the lens will allow you to shift the plane of focus (and focus the lens), giving you the shifted plane of focus you want.
However, it sounds easier than it is, as the slightest adjustment to the camera or lens can throw everything off.
The lens you use will also determine the success of your results – longer focal lengths, manually selectable apertures and full-frame (or medium-format) lenses are all things to look for.
You will need a fair amount of patience as well!
As no lens is attached to your camera, if you are worried about getting dust on your sensor freelensing may not be a technique for you.