October 19, 2021

I, Science

The science magazine of Imperial College

Taken from Issue 21.

You’d be forgiven for thinking that this photo was an intricate model of a train set – but you would be mistaken. It is, in fact, a photograph of a life-sized DART train in Dublin, combined with some post-production magic to fool us into thinking it is tiny.

This effect, known as ‘miniature faking’ or a ‘diorama illusion’, takes advantage of the shallow depth of field we normally encounter with macrophotography. Unavoidably, depth of field always decreases as magnification increases, so by blurring parts of the photo and simulating a shallow depth of field our brains are fooled into thinking we are actually seeing a miniature model. This can be achieved optically by using a tiltshift lens, or by applying the effect digitally in post-production.

With a tilt-shift lens, it’s possible to physically tilt the front portion of the lens. This sets the plane of focus at an angle to the image plane – something not normally possible with a regular lens, which has all the lens elements in parallel. This creates a short band of the image that appears in focus and leaves the rest of the image as a blur thus simulating a very shallow depth of field. With image-processing software, a similar effect can be achieved with a combination of gradients and blur filters.

For the best results, these images are normally taken from a high vantage point as if the viewer were looking over a diorama in a museum. It even helps to boost the colour saturation to mimic the brightly coloured paint used in miniature scale models. All of these techniques combined show how accustomed we have become to depth of field in photographic representations of the world – and how easily our visual perception can be fooled.

Image: flickr | Miguel Mendez