View Camera - Lenses

Lenses

A view camera lens typically consists of:

• A front lens element, sometimes referred to as a cell.
• A shutter, which consists of an electronic or spring-actuated iris which controls exposure duration. Some early shutters were actuated by air. For long exposures, a lens with no shutter (a barrel lens) can be uncovered for the duration of the exposure by removing a lens cap.
• The aperture diaphragm
• A lensboard: a flat board, typically square in shape and made of metal or wood, designed to lock securely into the front standard of a particular view camera, with a central hole of the right size to insert a lens and shutter assembly, usually secured and made light-tight by screwing a ring onto a thread on the rear of the lens assembly. Lensboards complete with lenses can be removed and fitted very quickly.
• A rear lens element (or cell).

Almost any lens of the appropriate coverage area may be used with almost any view camera. All that is required is that the lens be mounted on a lensboard compatible with the camera. Not all lensboards work with all models of view camera, though different cameras may be designed to work with a common lensboard type. Lensboards usually come with a hole sized according to the shutter size, often called the Copal Number. Copal is the most popular maker of leaf shutters for view camera lenses. The following is a list of the Copal Number and the corresponding hole diameter required in the lensboard to mount the shutter:

• Copal #00- 26.6 mm
• Copal #0 - 34.6 mm
• Copal #1 - 41.6 mm
• Copal #3 – 65 mm
• Copal #3s - 64.5 mm

The lens is designed to split into two pieces, the front and rear elements screwed, usually by a trained technician, into the front and back of the shutter assembly, and the whole fitted in a lensboard.

View camera lenses are designed with both focal length and coverage in mind - a 300 mm lens may give a different angle of view (either over 31° or over 57°) depending on whether it was designed to cover a 4×5 or 8×10 image area. Most lenses are designed to cover more than just the image area to allow camera movements.

Focusing involves moving the entire front standard with the lens assembly closer to or further away from the rear standard, unlike many lenses on smaller cameras in which one group of lens elements is fixed and another moves.

Very long focus lenses may require the camera to be fitted with special extra-long rails and bellows. Very short focal length wide-angle lenses may require the standards to be closer together than a normal concertina-folded bellows will allow; a bag bellows, a simple light-tight flexible bag must be used. Recessed lensboards are also sometimes used to get the rear element of a wide angle lens close enough to the film plane; they may also be of use with telephoto lenses, since these compressed long-focus lenses may also have very small spacing between the back of the lens and the film plane.

Zoom lenses are not used in view camera photography, as there is no need for rapid and continuous change of focal length with static subjects, and the price, size, weight, and complexity would be excessive. Some lenses are "convertible": the front or rear element only, or both elements, may be used, giving three different focal lengths, although the quality of the single elements will not be as good at larger apertures as the combination. These are popular with field photographers who can save weight by carrying one convertible lens rather than two or three lenses of different focal lengths. Older convertible lenses may not be corrected for chromatic aberration, making them useless with color film.

Soft focus lenses introduce spherical aberration deliberately into the optical formula for an ethereal effect considered pleasing, and flattering to subjects with less than perfect complexions. The degree of soft-focus effect is determined by either aperture size or special disks that fit into the lens to modify the aperture shape. Some antique lenses, and some modern SLR soft focus lenses, have a lever which controls the softening effect by altering the optical formula.

Current large format lens manufacturers:

• Schneider Kreuznach - Price-no-object high quality lenses.
• Nikon - Noted for its high quality telephoto designs. As of January 2006, Nikon announced it would discontinue manufacturing its LF lenses.
• Rodenstock - Extremely high quality, reasonably priced.
• Fujinon - Has a strong presence in Asia.
• Cooke - Interesting and expensive soft focus and color-corrected convertible lenses.
• Congo - Budget lenses, but offering interesting soft focus and telephoto designs.
• Seagull/Shen-Hao/Sinotar - Budget lenses.
• Wisner - Offer a modern convertible Plasmat set.
• Sinar - Zeiss, Schneider and Rodenstock lenses.
• Caltar - Rebranded Rodenstock lenses.
• Linhof - Rebranded Rodenstock and Schneider lenses.