What is 3D Photography? | how it works? | Basics of three dimensional photography
Hello everyone. Welcome to photographycinema. Today we see about an interesting topic that many people like. That's 3D-Three dimensional photography. Most of the people likes it, but they don't know how it is made. So, today we going to see about how it is works and some basic imaging process.
When we look at the world around us, see it from two different viewpoints at the same time. Our two eyes are separated from each other by a distance of approximately 2½ inches. Each eye sees an object from a slightly different point of view. The two images are combined in the brain so that we are able to see not only the height and width of things, but also their depth and distances from us and within the subject planes.
Thus we are able to see all the three dimensional- Height, width and depth, hence the term 3D.
How 3D photography works
All true 3D systems take two pictures of a subject from two view points separated by a horizontal distance which is at right angles to the subject being photographed. This distance is called the " Interaxial " of the 3D system. This in the case of our eyes will be 2½ Inches. The resulting two pictures will then represent the two views our eyes would have seen if we had been standing at the camera position . For this reason they are called right-eye and left-eye views. To get these two views we need two cameras or one camera with two lenses which takes the two views and records them separately on one piece of film.
In addition to the Interaxial displacement, two cameras (or the stero lens) must be capable of converging in the fields of view of the two pictures. Objects at the point of convergence will appear to be on the plane of the screen. Those objects between the camera and the point of convergence will appear as if it is in front of the screen. Those behind the plane of convergence will appear farther from the screen.
In a true 3D system, some method must be used to ensure that in the presentation the right eye of the spectator sees only the right-eye view of the stereo picture and the left eyw sees only the left-eye view. This " coding " and "decoding " of the stereo images the various processes differ.
Basically there are four different types of 3D imaging processes.
- The Stereogram
- Anaglyphic 3D
- Lenticular 3D
- Polarized 3D
The Stereogram
Two pictures (right-eye views) are taken and prints or transparencies are made and mounted. This stereo slide is then placed in a viewer which physically blocks the right eye from seeing the left - eye picture and vice versa (coding of views). The advantages of such a system are that full colour stereo pictures can be viewed and no complicated apparatus is needed. However, in motion pictures such a system would be impractical since they cannot be projected onto a screen for viewing by large audience.
Anaglyphic 3D
The principal photography is done by two cameras or one camera with stereo lens (to obtain right and left-eye views) and in projection, the two views are coded with two complimentary colours. One view may be coloured red and the other blue for example. Both images are projected simultaneously and superimposed onto a screen.
To decode them for the eyes of the viewer, a special pair of glasses made up. One lens is a red filter, the other is a blue filter. When a spectator in the audience looks through them, this is what happens; both the pictures are reflected from the screen and hit the outside of each filter of the glasses. In the case of the red filter, the red image passed through and looks light to the eye. The blue image is blocked and looks dark (or black) to the eye. The eye behind the red filter sees only the red image, the blue one being" blacked out ". A similar thing happens to the eye behind the blue filter of the glasses. This is how the right and left-eye views are coded and decoded.
The main advantage of this method is the fact that the two views can be printed onto colour print stock (with appropriate filteration). This eliminates special projection conditions. The disadvantages are that full colour motion pictures are not possible and the coloured glasses cause eye strain and headache when used for feature length period of time.
Lenticular 3D
In this method the disadvantages are, the great effort in designing the screen and building it, and determining from what angles the two views should be projected, as well as the fact that a good 3D effect can only be seen from limited viewing zones in the theatre. These limitations make this system impractical for a large audience even though it is full colour, glasses-free 3D system.
Polarized 3D
If everything has been set up correctly, this will be the right- eye image. The same thing happens with the left-eye. Since the polarizing filters, both in projection and in the viewing glasses, are neutral (gray), colour values are not affected, so full colour motion pictures are possible. This is the main advantage of polarized 3D. The main disadvantages are, that this method requires a silver screen and a special projection set up presently.
Polarizing 3D seems to be the most popular and widely used system. Many of the 3D films failed to survive because of bad technical quality in photography as well as poor projection, which caused considerable eye strain and discomfort to the audience.
Given below are a few hints for a better 3D image.
For better 3D:-
- Colour is an important factor in 3D. Most of the pictures made earlier were dull and washed out. Try to enchance colour in costumes, sets and backdrops. Unlike the normal photography, in 3D overcast days produce duller colour which turns out to be dark and murky in projection. Bright sunshine is preferable.
- Contrast tends to become more in 3D than normal. Blacks grow blacker. 25% more light is needed in shadow areas than normal. High contrast causes ghosting or colour fringes. Be careful of placing dark objects against very light areas or vice versa.
- Extreme closeups against distant backgrounds produce an abnormal phenomenon called divergence which causes eye strain. The solution is to look for neutral or closer backgrounds or to use lighting to diminish the background
- Lightning is an important tool in 3D for controlling visual effects. It can add or subtract depth to the subjects being photographed.
- Focus is an essential factor in 3D. Every thing in frame should be in sharp focus. Out of focus foregrounds looks bad in 3D.
- Objects which seem to extend into the audience from the screen should not be, cut by the frame edges as this will spoil the illusion.
- When an object appears to come off the screen, the eye and its muscles should be given enough time to follow and be disciplined to the 3D effect. In such cases slow motion is very effective.
- Rapid cutting helps the 3D effect. When the viewer starts comparing background and foreground, the magic is gone.
- Dolly shots, moving in and going away are wonderful in 3D. Fast pans don't work well as also focus shifts for emphasis.
- Use of interaxis greater than 2½ inches tend to make even real landscapes look like miniatures. Redirect interaxials cause object appear much larger than they actually are.
That's all viewers. Today we see some information about three dimensional photography and i hope this blog post will help you to upgrade your skills and knowledge. These are the basic process of three dimensional photography. If you have any questions or doubt please contact us or comment below.
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