- Here is the technique and the sensations of large format photography.
- In film photography, there are 3 types of format: the most common is the small format 24X36 mm which uses a 35mm film, then the medium format of 4.5X6, 6X6 or 6X7 cm which uses a 120 film and the large format which ranges from 10X12.5 cm (4X5 inches) to 20X25 cm (8X10 inches).
The model used is an Arca Swiss 4X5 monorail chamber from 1964, equipped with a Schneider Symmar 5.6 / 150 mm lens, which for the anecdote, can be transformed into 265 mm open at f / 12 by unscrewing the rear lens block . Swiss-made like Sinar, the Arca is neatly constructed and light enough for a studio room. It is perhaps for this reason that Ansel Adams chose this model to photograph the wide open spaces of the American West from 1964 to 1968.
Sensitive surfaces and chemicals are still available. Film plans are often sold in boxes of 25 sheets. The choice of sensitivity is quite limited from 100 to 400 iso. The loading of the double frames is done in absolute darkness before the shooting. They are often contained in a foldable black bag and protected from light by a three-part box. Notches at the top right when you hold the emulsion vertically in front of you can be identified. These notches are different for each range and brand. Small tip: the top of the shutter has a white side and a black side. The practice is to reserve the white side for blank plates. And after the exposure, turn the flap over to the black side to clearly distinguish the blank or exposed plates.
The installation:Study the light of the scene to be photographed, choose a position and define the framing.The light highlights the subject, in black and white a large angle will increase the contrast of the image.The position relative to the subject will determine the volume granted to the scene.The choice of framing will be the photographic interpretation, the bias.Install the tripod, adjust the base of the stand to the spirit level and fix the chamber. Open the shutter of the room to let in the light and open the lens at its highest value. Position the room according to the subject and the framing chosen after having made a focus of the fast distance. The image is displayed upside down on the frosted glass, the top is at the bottom.Little tip to save time: Anticipate tilt and shift movements from the moment of setting up during the framing, while checking the spirit levels on the lens and the back.
Focus:With a monorail camera, the focusing is done by moving the rear body. The lens does not move from the position set for the current photograph. There will still be the possibility of extending the front body for close-up shots. A magnifying glass is necessary to check the sharpness. The adjustment is made at full opening. The frosted glass is not bright, a black veil will allow you to isolate yourself.On the right, the focusing wheel which moves the rear carriage on the rail. In the center the back can slide for off-center. On the left the lever and the concentric button each have an immediate tilt action in both directions, vertically and horizontally.
The red lines explain Scheimpflug's theory : The possibilities of movement of the front and rear bodies are important.The shift allows to correct the perspective and find an image close to the real vision.The tilt offers the possibility of controlling the focus area. Position the back parallel to the most important line of the subject, center the back or the objective to respect the proportions.Then adjust the clear planes by tilting the lens and the back while remembering the Scheimpflug rule which states that if the planes of the subject, optics and film meet at the same point, the image will be sharp.
Light measurement: The Weston light meter will measure the incident light received by the subject, taking care to position itself in the axis of the objective. It is the surefire way to measure the exact amount of light unlike the measurement reflected by the subject.
Exposure adjustment: The check will give a value (13), for this scene. Set this value on the dial and displaying the sensitivity (ISO 125), the film chosen is an Ilford FP4. The disc offers all the choices of speed and diaphragm. On the Weston Master V it is not so easy to read. The choice of 1/60 - f / 18 will be retained and set on the lens.
The shutter which protects the film plane in the frame is removed when everything is set. Once exposed, simply slide the shutter again and remove the frame.
The shooting done either with a flexible shutter, or by pushing this lever gently, after having armed the shutter with the one which is above the lens.
Processing 4X5 in small tank : The film is loaded in the tank in the dark. Once closed, just 75 ml of development product. First the developer (Kodak D76 1/1 in lost bath - for 9 minutes at 20 °) stirred regularly. Then after a quick rinse, the fixer is needed for 3 minutes and a continuous wash for 10 minutes. Then a little wetting agent to avoid traces of lime on drying.
The tools : Flexible trigger, spirit level, Schneider X4 magnifier and Weston Master V light-meter. This selenium-powered model - does not need a battery. Its voluminous and particularly designed invercone gives it great accuracy in measuring incident light. The use of this vintage cell alone reminds us of missing gestures.