Forced perspective is a photographic optical illusion. It is generally used to make two or more objects appear closer or further away or of a different size than they are in reality.
In photography, forced perspective is made possible by the single lens of the camera. Unlike your eyes, which work in tandem to create depth perception, the camera has only one eye. As such, the camera has no depth perception and sees things as flat and two-dimensional.
Photographs in which one subject seems to merge with another, and those seeming to depict things or people defying gravity, are technically part of this genre of photography as well. However, they rely more on orientation and point of view than a true visual compression due to the single eye of the lens.
Indeed, even the "carried away by balloons" illusion technically falls into forced perspective. This is because the angle of view under the subject’s feet is compressed by the camera to create the illusion of more height.
Types of Forced Perspective
Forced perspective generally falls into a few main categories:
- Making a subject appear larger
- Making a subject appear smaller
- Merging subjects
- Defying gravity
Common Forced Perspective Photos
While the opportunities for forced perspective are nearly limitless, there are some "standard" photos that have become familiar. You've likely seen some of these around the internet, especially in quirky photos on social media:
- Holding or propping up a landmark
- Holding or eating the sun or the moon
- Holding another person in one hand
- A toy that's larger than a person or pet
- People hanging from the top of a photo
- A person stepping on another person
- An older photograph or a sketch merged over a scene
The process for taking a forced perspective picture varies depending on the type of forced perspective image you want to create.
Change a Subject's Size
Depth of field, distance, and line of sight are the three main ingredients in a size-changing forced perspective photo. This same technique was used in the movies for decades before computer graphics came along. "Darby O’Gill and the Little People" is a great example of a movie made using forced perspective.
When creating this type of photo, the subject that you want to appear smaller should be further away from the camera than the subject you want to appear larger. The distance depends on the size difference you want to achieve.
For instance, to shrink a pet you may only need 6 or 8 feet. To shrink a mountain, you might need a mile or more. The larger the size difference between the actual size and the desired appearance, the more space needed.
Most of these photos will be made with a wide angle lens (35mm or less) and a large f-stop setting. The exact f-stop required will depend on the distance between the two subjects.
- Use whatever setting is needed to put both subjects in focus.
- If you do not have manual focus control on your camera you can set the autofocus one-third behind your closest subject. This is because the depth of field (DOF) always falls one-third in front of the focal point and two-thirds behind the focal point.
Once you have determined the focus for your photo, you’ll need to set up the alignment. If the subjects are not touching in the photo, the alignment of the shot is not as critical. Proper alignment is essential when you want to make it appear as if the subjects are touching.
If you are setting up a photo where the subjects appear to touch, such as one person appearing to stand in another person’s hand, you may need a tripod. This will give you the stability needed for fine adjustments to the line of sight. It will also prevent gaps or overlaps of subjects in the wrong spots.
Merging subjects is also quite popular. You can see this in the trend of old photographs held in front of current versions of the same scene.
To merge subjects, you’ll follow the same process as the size change forced perspective photos. Instead of emphasizing size differences, however, you’ll make the old photo/sketch match the size of the current scene. Since you’ll be holding the old photo/sketch relatively close to the camera, a large f-stop (small aperture) and wide angle lens will be especially important to get both items in focus.
Defying gravity in a photo is one of the easiest forced perspective photographs to create. The basics of a gravity-defying photo are to turn the photo upside down or on its side.
- Subjects can lie down on the ground with their feet on a wall as though they were sitting against the wall.
- Multiple subjects can lie down on the ground at various locations so they appear to be flying.
- Subjects can lean out of doorways to give the illusion of hanging.
Don’t be afraid to experiment with your poses to find one that works best. Finding a location that works for this type of shot is the most difficult part.
To find a location, look for a spot where a subject can lie down on the ground in such a way that they look like they're sitting against a wall. You will also need the camera to be positioned where the wall looks like the floor.
Other good choices for location:
- Piers where reflections mirror the background
- Long hallways with doors or columns on either side that allow subjects to lean into the hallway. This can suggest hanging or climbing out of the ceiling/floor once the photo is turned.
When you turn the photo’s orientation to create the gravity illusion, remember that a straight horizon is very important so that you don’t shatter the illusion. Also, pay attention to the subject’s clothing and hair positioning. Hair and fabric that hangs differently than the apparent reality of the photo will quickly shatter the illusion.