Microdrive mechanism rotates camera for 360° roundshots
Modern electronic cameras are opening the door for totally new photographic possibilities, both for photos taken in situ and for post image processing. By combining the high resolution and rapid shot frequency that can be achieved nowadays with a "rotating turntable", so-called panorama shots can easily be compiled. The basis for this, along with a top-quality photographic device, is optimal camera or lens focusing over the swivel range. A compact camera with microdrive motor offers optimal "small-footprint" results in this field.
Over time, classical photography has undergone a huge change. Electronic systems have superseded the process of recording images chemically. Yet even modern photography is subject to the laws of physics and visual appearance. The extensive equipment that was once necessary has nowadays been whittled down to better lenses, digital zoom technology and compact image storage, yet despite this the camera still has to be positioned so that it doesn't shake. This is especially important when taking roundshots. Seitz Phototechnik AG, based in Lustdorf in Switzerland, offers the ideal solution for these types of shot sequences. With the help of Roundshot VR Drive, cameras can be equipped for "panoramic view" quickly and cost-effectively. Alternatively, it is possible to capture a rotating object while keeping the camera at a fixed position. A micromotor supplied by drive specialist FAULHABER serves as the drive mechanism in the miniature auxiliary device weighing only 2.3 kg.
The compact Roundshot VR Drive is suitable for many SLR cameras and allows an unprecedented variety of shot perspectives. Image: Peter Seitz (www.roundshot.ch)
Panorama precision. Even in the age of digital image processing the old truth still applies: whatever has been "captured" correctly when taking the shot will not then have to be laboriously corrected later. Especially when creating a composition from several individual images, having individual shots that match up exactly makes it easier to stitch them into a seamless, all-encompassing view. In turn, a high shot frequency together with exact blending of the individual angles of vision lets moving objects such as clouds or vehicles seem to freeze. The VR Drive automatically rotates the camera smoothly, avoiding jerky movements, and takes pictures on request. With up to 999 stops per 360° rotation, top-quality panoramic views can be generated. The state-of-the-art panorama head provides photographers with high-end technology for a wide range of applications. The Roundshot VR Drive "s" speed achieves a full 360° rotation in only four seconds. Depending on the camera, up to 5 pictures per second can be taken in quick sequence in automatic mode. In the process, precision and smooth motor rotation allow a higher resolution than would be possible with manual panoramic heads. The quick rotation speed, combined with the high individual shot frequency also solves the problem of "ghost" images that occurs with moving objects such as, for example, people or clouds. Even cylindrical or spherical panoramic shots (see boxes) can be taken quickly and cost-effectively with many digital SLR cameras and with all lenses, from fisheye to telephoto. In combination with the high-performance image processing software, the system also allows you to create HD videos or time lapse films. In doing so, it is possible to have up to 999 positions in a 360° rotation – ideal for gigapixel photography. When the shot scenario requires a higher dynamic range the VR Drive activates its quality mode, thus positioning the camera for automatic bracketing. Within this context, the object is photographed several times in order to obtain a higher dynamic range. The images, with exposure levels, are subsequently processed to a 32-bit HDR image, e.g. for 3D modeling or film production. In principle, however, the following always applies: the more precisely the camera is used, the simpler the subsequent image processing becomes. The Swiss experts in dynamic photo technology therefore attach great importance to a precise yet at the same time practicable and robust drive mechanism.
Panoramic shots unlock new opportunities when compared with conventional techniques. Image: David Osborn (www.britishpanoramics.com)
Compact drive technology. The drive mechanism for adjusting the camera position is therefore subject to specific requirements. The ideal actuator must deliver a high performance while taking up the least space possible. Since considerable freedom of movement is neces-sary for the best visual motif, the drive mechanism requires a high degree of efficiency in order to utilize the limited capacity of the lithium ion accumulator to its optimal level. An exact correlation between the control command parameter and actual movement of the drive mechanism is essential for precise positioning. Here, motors with integrated encoders bring optimal field signal results. Last but not least, all movements must always be executed dynamically in the same way, regardless of the weight and camera model fitted. A precious metal commutated standard DC motor with diameter-compliant gearhead and encoder attachments came out on top as the drive mechanism of choice given all the stipulated characteristics. Depending on the model, the 22 mm diameter drive mechanism supplies between 2 and 11 Watts and achieves a turning moment of 2.5 to 10 mNm at the output shaft. The voltage variants lie between 3V and 40V. With an efficiency rating of over 85 %, the motor, which can optionally be equipped with sintered sleeve bearings or, for continuous operation, with ball bearings or pre-stressed ball bearings, is ideally suited to battery-based applications. A fitted planetary gearhead reduces the motor's rotational speed as appropriate, increases the output torque, and at the same time improves the resolution of the encoder fitted to the motor shaft for the output side of the gearhead. Reductions in a ratio of 3.71 to 23.014: 1 are possible in plastic or metal gearhead models. The outflow torque may account for up to 700 mNm. Depending on the chosen reduction (2-6 stage process), the gearhead's efficiency rating lies between 50-88 % efficiency, protecting the battery. An optical encoder mounted to the motor shaft delivers 100, 500, 1,000 or 1,024 rectangular pulses per rotation, according to the model. In this way, not only tilt angles but also full circles can be completed in a targeted and fully reproducible manner. Furthermore, single frames can be shot with the requisite angular alignment. The comprehensive package, consisting of motor, gearhead and encoder, is low-maintenance and can be operated in a temperature range of between -40 to +100 °C. Thus, the only limiting factor when it comes to taking photographs of winter scenes on the one hand or desert images on the other is the battery supply.