PhotoFidelity

Wikipedia’s definition is a good starting point:

Forced perspective is a technique that employs optical illusion to make an object appear farther away, closer, larger or smaller than it actually is. It is used primarily in photography, filmmaking and architecture. It manipulates human visual perception through the use of scaled objects and the correlation between them and the vantage point of the spectator or camera.

You are probably most familiar with the use of forced perspective through its use in movies. Lord of the Rings’ (LOTR) trilogy used this to great effect, making normal-height actors appear as smaller hobbits and dwarves. For video explanations of how this effect was achieved, view these brief clips:

• LOTR Forced Perspective (2:51 min)
• LOTR Forced Perspective Moving Camera (2:35 min)

The forced perspective illusion usually, though not always, occurs when objects are incorrectly perceived as connected together in some way. The apparent connection can be either physical (e.g., they appear to touch) or visual (e.g., a hobbit looking up at a human in LOTR). That is, they appear to be interacting in a way that implies they are physically close. Once our mind is deceived into thinking they exist near each other, it has no choice but to incorrectly misinterpret their sizes.

For the effect to work well between two objects:

• both objects should have roughly the same lighting and perceived sharpness,
• should appear connected in some way, either physically or visually, and
• the presence of other perspective cues, which might disrupt the illusion, should be minimal.

Forced perspective is not limited to objects in physical or visual proximity. There are other ways of having real-world subject distances and sizes appear distorted in a picture, not covered here. In effect, forced perspective is a result of misjudging distances due to misleading visual cues.

The Dwindling Size Perspective post summarized how we unconsciously judge distances to similar objects based on their relative size differences. Here we see similar objects—for example, actors in LOTR—that differ in image size and yet look as though they’re the same distance from us. Are not these two concepts in conflict?

In the previous perspective post, there were other cues present such as Height, Linear, and Overlap perspectives (we’ll cover these in later posts) which prevent the illusion of forced perspective. The photos in that post were also lacking the connectedness between similar objects required by forced perspective.

SUMMARY

Our binocular vision is useless in determining distances in a two-dimensional image. So we rely solely upon other visual perception cues to judge distances. This is why it is crucial for us, as photographers, to be knowledgeable about perspective cues. We should also be aware of how to use them to our advantage. By providing perspective cues, that visually evoke the sense of distance within our photos, we add a sense of realism.

In the end, forced perspective can either be good or bad. It all depends upon whether it was intentional.

EXAMPLES

This first example works because we expect to see water flowing from a water bottle. It also appears as if he is looking at the water, which adds to the illusion that the bottle and water are connected. Even though we know it is a distant waterfall, we see it as coming out of the bottle.

  by   Craig Murphy  

This example appears to violate what we learned in dwindling size perspective. That’s because they are visually connected at the feet, which can only happen if they are in the same vertical plane. This perceived connection overrides the visual cue of dwindling size and produces the illusion of having drastically different heights.

  by   abmiller99  

This illusion is not as strong as some of the others. This is partly due to: slight differences in lighting and the steam is visually anchored to the ground. But, that shouldn’t stop someone from creating a fun shot like this.

  by   toastforbrekkie  

This is the cliche shot for all large monuments around the world. The illusion would be stronger if not for the people. Their presence disrupts the effect on the bottom.

  by   danorbit.  

Here is a photo of the monument which undoubtedly gets the most forced perspective abuse: the Leaning Tower of Pisa. After all, the tower is just begging for some support. Visit The Art of Gesture in Tourist Italy to get an idea of the magnitude of this unsolicited help.

  by   Andy Hay  

Here is an example of the dreaded “limb growing from head” shot — in this case, a cactus. The illusion wouldn’t necessarily be apparent to a photographer. In real-life, binocular vision easily discerns object distances in cases like this. This is why it’s important to check your background when shooting.

  by   johnhallassoc  

And now for the coup de grace. Here’s the monument shot combined with the “limb growing from head” shot. Even though we know that the Washington Monument is quite some distance away, visually it appears anchored to this poor soul’s head; thus, appearing to be in the same vertical plane. This could be a good way to have fun at an unsuspecting subject’s expense. Though it might be better to try and avoid this type of photographic faux pas.

  by   Abeeeer  

Update on Friday, February 5, 2010 at 7:16PM by Daniel Fealko

For another excellent example of forced perspective use, check out Michael Paul Smith’s photos using models (here).