@Lesnums) Posted on 14/03/17 at 15:30 Share:
In photography, the notion of technological progress sometimes follows very strange paths: while the medium format market is experiencing a revival today with the release of the Hasselblad X1D and Fujifilm GFX cameras, large format are also experiencing renewed interest from photographers, not only for the image quality and the possibilities they offer in terms of shooting, but also for the originality of the photographic practice they induce , the latter reconnecting with shooting times in opposition to the urgency of our modern uses. Let's explore the shooting system that is the photographic chamber.
Definition and principle
Allowing greater image control than conventional cameras and thus being intended for professional photographers, the view camera — or large format camera — is a relatively rudimentary photographic device developed from the middle of the 19th century. It is characterized in particular by the use of photosensitive surfaces of a size greater than the standards that constitute the medium format, themselves greater than the 24x36 standard. While glass plates were originally used, they have since been replaced by film planes and digital backs, which typically range in size from 4 x 5" (10,16 x 12,7 cm) to 8 x 10" (20x25cm). Some higher formats are sometimes used, but they remain relatively marginal.
Comparison between 24x36 format (35 mm), medium format (4,5 x 6, 6 x 6, 6 x 7 and 6 x 9 cm) and large format (4 x 5 and 5 x 8 inches).
Although there are several physiognomies of large format cameras, these consist of a front body supporting the lens, a rear body supporting a focuser, a film holder frame or a digital back, an optical bench and its support in order to vary the distance between the first two elements, as well as a bellows with light-tight walls and forming a dark room, inside which the light rays travel from the lens to the photosensitive surface. It should be noted that this type of photographic system often favors central shutter lenses.
However, there are 3 main types of large format rooms. Profiting from a contained weight and a consequent robustness, the cameras of the folding type authorize only limited movements, but can be transported and were thus very popular near the journalists as of the end of the 19th century. More cumbersome and requiring the use of a tripod, folding chambers — or field cameras — have an optical bench formed by a folding and extendable panel. Often used in landscape or architectural photography, these cameras can manage more substantial shifting and tilting operations than the folding camera. Finally, it is the monorail chambers that allow the greatest range of motion; these modular devices are however not very portable and are therefore intended for the studio.
Penta 45F folding chamber.
Advantages and disadvantages
The main advantage of a large format camera obviously lies in the large size of the film plane or the sensor used. Such formats ensure high accuracy in the transcription of colors and details, as well as low loss of information when creating large prints. If it is difficult to objectively judge the quality of the bokeh, it should be noted that the size of the photosensitive surface has a direct impact on the depth of field, and consequently the aesthetics of the photographs obtained (at equivalent shooting parameters , the larger the size of the photosensitive surface, the smaller the depth of field).
We will not return here to all the technical notions detailed in our recent tutorial on tilting and shifting, but it is important to remember that the front and rear bodies of a view camera can be moved in such a way as to offer a certain control over focus distance, depth of field and perspective. The precision offered by a device of this type makes it a privileged tool for fields such as architectural photography and the reproduction of works of art.
Among the 3 types of possible movements, the movements of the lens plane are used to control the focusing: it is done by moving the rear body along the optical bench. The action of shift designates the movement in its plane of one of the two bodies of the camera out of its normal position in order to modify the framing of the image — the shift can be horizontal or vertical. Called rocking, the last possible movement consists of a modification of the angular position of one of the two bodies of the chamber; it has the effect of modifying the perspective and the plane of sharpness of the image.
Off-centering and rocking movements of the front body.
These different movements also grant certain freedoms as to the orientation of the plane of sharpness. Thanks to Scheimpflug's optical law, we can compensate for a shallow depth of field by orienting the plane of sharpness so that it intersects the subject in its smallest thickness. Conversely, the "anti-Scheimpflug" technique consists of using the same principle in order to minimize the sharpness zone of the image. It is thus possible to obtain "miniature" or "model" type effects now well known to the general public.
As you will have understood, such control over the image cannot however go without some drawbacks. Large-format devices are heavy and bulky on the one hand, and on the other hand more complex to use than conventional devices. Although they are suitable for certain specific photographic disciplines, they often have to be used with an imposing tripod and deal with the slowness of operation induced by the careful adjustment of parameters (focusing on frosted, shifting and tilting movements, etc). Apart from a few high-end models, it should also be noted that most view cameras do not incorporate any automation or light metering system. It is therefore necessary to use an additional accessory, such as a light meter, in order to determine the correct exposure.
Sinar F monorail chamber.
It should also be noted that the question of cost can be considered as a major drawback of the practice of the view camera. Cameras, lenses, films, digital backs and other accessories are expensive. The entry ticket to the world of large format is high and requires serious preliminary consideration as to the compatibility between such devices and your photographic practice.
To conclude
Although they have existed since the origins of photography, large format cameras are very special tools. The choice of such a tool implies adhering to a very different photographic time from that to which we are accustomed to the cameras full of automatisms that populate our camera bags and our pockets. However, these very different practices complement each other more than they oppose each other.
Cambo Actus Mini and Sony A7R mirrorless camera.
If it is impossible to take advantage of the image quality provided by very large films and sensors other than through a view camera, several more conventional solutions can be considered in order to experience perspective control. and depth of field. Some architectural photographers thus equip themselves with a tilt and shift lens with classic reflex cameras, while Lensbaby brand optics make it possible to play on the level of image sharpness while maintaining a relatively low price. . We also note the appearance on the market of devices such as those put forward by the Cambo Actus range, which mimic the operation of a large format camera on many points, but rely on reflex or hybrid cameras as a digital back.
