Since the beginning of 2011, Olympus Imaging has introduced a number of 3D-enabled cameras that use 3DMedia’s ViewFusion technology. This document provides information to help advanced users of Olympus 3D-enabled cameras to create better and more immersive 3D photos to enjoy for generations to come.
3D Camera Overview
Olympus 3D-enabled cameras are standard, single-lens cameras with special software that allows users to create 3D content. These models include Olympus SZ-10, SZ-20, SZ-30, and TG-310. To capture 3D images, users need to take two pictures by moving the camera to different positions between shots, thereby creating the same effect as a dual-lens camera. The process is rather simple. With automatic 3D mode, the user takes the first picture and then moves the camera to the right in a lateral manner. When the camera is at the right distance, the second picture is taken automatically. After the two pictures have been taken, software running on the camera creates a 3D image that can be displayed on a 3D-enabled HDTV using the provided HDMI connector, or can be downloaded and enjoyed on any 3D-enabled PC or laptop. In addition to the automatic mode, Olympus 3D camera models offer a manual mode that provides the user with more flexibility when creating 3D content.
One limitation of dual lens/sensor cameras is that they have fixed stereo baselines and fixed lens orientations (parallel, converged, diverged). The fixed configuration limits their ability to capture close objects and/or very distant objects. In the latter case, after a certain distance all objects look flat, the same way we lose our perception of depth when viewing a scene with our eyes. This may not be obvious, since the human brain can extrapolate depth using different cues the same way we can perceive depth even in 2D photography. Olympus 3D-enabled cameras can vary the stereo baseline, and therefore are not subject to such limitations. Olympus cameras have the ability to analyze the scene and provide guidance on how far apart to take the two pictures. In all models available today, this process is done automatically. In this case, after a user takes the first picture and starts sliding the camera to the right, it automatically takes the second shot when it reaches the correct distance.
One drawback of using 3D-enabled or standard cameras to capture 3D pictures is that since the two pictures are taken at different times, there may be movement of objects in the scene. Tools or technologies that compensate for object movement between shots are needed to create the best experience in creating 3D content with single-lens cameras.
3D Photography Techniques
3D photography is an exciting way to capture content. It presents some new challenges, but it also allows users to create pictures that are more visually exciting and immersive, thus enhancing the experience. Shooting in 3D is different in some ways compared to traditional 2D shooting. The main reason is that in 3D, a new dimension needs to be captured and framed appropriately. Although many aspects of traditional 2D photography also relate to 3D, some techniques that apply to 2D photography may not be appropriate for shooting in 3D. In this section, we describe general shooting methods that result in the optimal 3D experience for Olympus 3D cameras.
One important aspect of 3D photography is the distance between the two images, known as the "stereo baseline". The stereo baseline plays a very important role in 3D photography since it determines the depth of the scene. The stereo baseline of human eyes, also called the binocular distance, is typically 5-6cm. Humans also have the ability to angle their eyes so they converge or diverge. In a stereo camera, the camera position is generally fixed, meaning that the baseline is fixed as well. However, shooting objects at close distances requires a relatively small stereo baseline (even less than 0.5cm in some instances) or a converged configuration, and when shooting distant objects, using a much wider stereo baseline (even much larger than the binocular distance in some cases) or a diverged configuration often yields the best 3D results.
When advanced users photograph objects at far distances (for example, scenes with the nearest objects more than 10m away), it is recommended that they use the manual mode to further increase the stereo baseline, thus generating a more pronounced depth in the resulting 3D photograph. When performing this technique, users need to slide the camera laterally, past where the overlaid first picture would indicate, then press the shutter button manually when they reach the desired distance. Guidelines for determining the optimal distance are provided in the following paragraph.
Although the choice of stereo baseline depends on many factors such as focal length, aperture, etc., a rough guideline is between 1/30 to 1/60 of the distance to the closest object in the field of view. For example, if the closest object is 3m away, a stereo baseline in the range of 5-10cm would be suitable, depending on the total depth of the scene and other factors. Though oversimplified, this is a good starting point for experimenting with 3D photography. Note also that the closest object is often the ground, and if so, this should be used as the reference to calculate the stereo baseline.
It is very important to understand that different people have different preferences and sensitivity to the depth of 3D content. Some prefer more depth, but for others even smaller amounts of depth may be uncomfortable. Therefore, it is recommended that each user experiments with stereo baseline selection to determine his or her preference.
When using 3D-enabled or standard cameras, one must also consider the direction and angle to move the camera before taking the second picture. For the best 3D effect for the overall picture, it is recommended to move only laterally either to the left or right, avoiding any toe-in towards the main subject or toe-out away from the main subject. In other words, it is preferred to take both pictures with the same lens angle rather than re-centering the subject for the second shot.
3D photographers need to account for a new element that does not exist in standard 2D photography. This is the third dimension, or depth of the picture. Good depth composition is very important to create a realistic, immersive, and exciting 3D photograph of a scene. Traditional 2D shooting techniques may not necessarily produce the desired effects in 3D photography. When composing a 2D photo, the photographer makes sure that various subjects/objects are well balanced within the two-dimensional space. In 3D photography, the same principle should be applied to the third dimension. Taking a 3D photo of a flat surface or a scene where the subject is at a great distance and the background is at a focal distance of infinity (e.g., sky) does not typically produce an excellent 3D effect. For a good 3D photo there should be a depth continuum. This can be achieved using various compositions. The ground can be a useful element, as the ground spanning from the bottom of the field of view in the photo to some distance can provide a sense of depth continuity. One simple 3D compositional technique is to have multiple subjects at different depths. Another effective technique is to arrange objects so they are placed across the third dimension. For example, when taking a photo of a large object, placing the width of the object across the third dimension can help create a sense of depth.
Large breaks in the depth continuum can produce the undesirable “cardboarding” effect. This makes pictures look like flat objects (cardboard figures) placed at different depths in the scene. This is more likely to occur when the volume of the objects in the scene is small compared to the total depth of the scene. In this case only a few levels of depth are visible, and the transitions between levels appear to be discontinuous and unrealistic. Since the goal of stereo photography is to reproduce the feeling of being at a scene, stereo photography is also generally not conducive to low-light conditions that would limit that perception (and again, be more likely to add noise).
Another advanced aspect of 3D photography is aligning the main subject within the picture. The photographer must account for the fact that the camera will slide between pictures. For example, in 2D photography the main subject is often centered in the photo. If a centered subject is desired in a 3D photo, the main subject should be positioned slightly to the right of center in the first shot, such that the subject will be slightly to the left of center in the second shot. If this technique is not followed, photographers will have to resort to cropping after producing the initial 3D picture.
Another non-intuitive aspect of 3D photography is the selection of focal lengths. It is better to use smaller focal lengths when possible. Our preference is to shoot at 28 and 35mm. Longer focal lengths result in a smaller field of view and therefore less total depth in the scene. Longer focal lengths also tend to create more cardboarding effects since there is already compression of the scene and therefore less depth continuum. Shorter focal lengths typically capture a larger field, which should usually have more depth. However, when shooting at shorter focal lengths, one should be careful to check whether objects on the edges of the field of view are in fact the closest objects, as this requires the stereo baseline to be adjusted accordingly. It should be noted that not all cameras allow users to choose focal lengths when shooting in 3D mode.
3D cinematographers use the perceived depth (i.e., depth budget) of a scene as a storytelling device. This is because different emotions can be created by playing with perceived depth parameters and the time those parameters are applied in a sequence. The same is true for still photography, and to a certain extent the most appropriate depth of a scene depends not only on user preferences but also the context of the scene. When properly done, 3D photography naturally provides a better viewer experience. However, it is also possible to create boring or exhilarating 3D content the same way that it can be created in 2D. Manipulation of depth and other 3D parameters provide additional artistic elements to photography. Photographers from novice to professional should consider 3D as a new opportunity for expression that can touch the viewer in a more emotional way.
Olympus 3D-enabled cameras provide a new way to create and enjoy personal content. Their technology allows users at all skill levels to easily create immersive and realistic 3D photos. Go ahead - try them! They are great products that will allow you to experience photography in a whole new way.
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