Art 122 Digital Photography

What is large format?

Cameras are often divided into groups by the general size of the film that they accept. Large format cameras usually use sheet film that is 4" x 5" or larger (though the cameras can be modified to take smaller films). Medium format cameras generally take large roll films, like 120. Miniature cameras (you don't hear that term much anymore) take 35mm.

What is a large format camera?

Large format cameras tend to be view cameras, which is itself a generic term. View cameras are generally configured to have a rail or a flat bed running horizontally. There is a front standard where the lens is attached. There is a rear standard that holds the ground glass (for focusing) and the film. In between the standards is a light-tight bellows or bag. The image is focused by changing the distance between the two standards. The standards may also have movements that allow them to tilt or swing relative to each other. These movements allow the image to manipulated in camera for various effects.

The Advantages:

Image control. Large format cameras have moveable lenses and film

planes, which allow a lot of optical effects that are not possible with

cameras where the film plane and lens is fixed into a permanent

position. Depth of field can be manipulated in more ways. Image

perspective can be altered. And views can be framed in camera (to some

extent) without moving the camera position.

Minimization of grain and enlargement. Smaller formats have to be magnified much more than large formats to get the same print size. Since magnification shows grain, resolving power limitations, and defects on the negative, images that are magnified less tend to look sharper, smoother, and cleaner. Very large formats (such as 8x10) can be directly contact printed into large photographs with no magnification at all.

The disadvantages:

Expense. Just about anything that has to do with large format is going to cost more than smaller formats. The lenses are more. The cameras are more. The film is more. The enlargers are much more.

Time. Large format cameras and techniques are not honed for speed.

Large format cameras require tripods, careful focusing, and adjustment of the camera movements to obtain a desired effect.

Kinds of view cameras

Field cameras are the typical and classical view camera. A field camera

is generally intended to be used outdoors. They are often designed to

be rugged, lightweight, and compact. They usually have flat beds on the

bottom that are hinged to the back (rear standard), which gives a very

sturdy platform. They usually have limited or moderate movements and

the flat bed folds up to protect the front. Typical field cameras

include offerings by Zone VI, the Toyo-field 45AII, and the Horseman

45FA.

Studio cameras, often also known as monorail or technical cameras, tend to be designed to look like an optical bench. They usually have one rail (hence monorail that runs horizontally with the front and rear standards attached to it so that they can slide along the rail's length. The rail is mounted on a tripod or equivalent support. The front standard, rear standard, and the bellows tend to be detachable and modular, allowing interchangeability with other standards or accessories (such as extra-long bellows, bags, larger or smaller backs, etc.). They also often have their movements marked and graduated so that the camera's position can be recorded and duplicated. Popular studio cameras include offerings by Sinar, Calumet, Toyo and Horseman.

Press cameras are fairly rare today--the name derives from large format cameras used by press (newspaper) photographers. They tend to have limited or no movements. They tend to be compact, lightweight, and rugged. The big differences between press cameras and traditional field cameras are that press cameras are meant be hand holdable, are meant to be focused with a viewfinder instead of a ground glass back, and have limited or no movements.

Sizes of film

Sheet film is typically measured in inches. The most common (and smallest)

size is 4x5. The two other common sizes are 5x7 and 8x10. There are also

less common sizes available, such as 11x14 (which many people like because

it contact prints a large photo).

Descriptions of the Camera.

á The rail:

á Front and Rear Standards:

á Bellows:

á Spring Back:

á Ground Glass:

á Lenseboard:

á Lens and Shutter:

á Film Plane:

á Lens Plane:

Camera Movements

Movements allow the front (lens) and rear (film) standards to be adjusted relative to each other, which allow for special optical effects. For the purposes of this discussion, I'll define neutral or normal position as when the lens axis (an imaginary line that runs through the optical center of the lens) is perpendicular to and centered on the film plane. This is the configuration almost all cameras normally have. Most cameras are fixed in this position. View cameras, however, can change this.

Camera Movements: Increases your ability to control:

á Perspective: relative sizes of objects in an image.

á Plane of focus: the plane in front of the lens in which all points are in focus.

Perspective:

Have you ever looked at a photograph of a skyscraper (or any tall building) and it looked like it was collapsing because the walls were converging? This is called keystoneing. It usually comes from tilting a camera upward--parallel lines converge and the perspective is loused up. Large format cameras can correct this--if the camera is pointed upward, the standards can be tilted so that the parallels no longer converge. This is invaluable in architectural photography.

Focus control:

With a fixed lens camera, depth of field is simply the area in focus from a certain minimum distance to a certain maximum distance. This area of focus is actually a three-dimensional space--and this space's position can be altered by the movement of the camera standards. A classic example is a photograph of a wall that runs diagonally from your camera position. Suppose that it is impossible, with a fixed lens camera, to get the whole wall in focus because the depth of field just does not get large enough to cover. A view camera can shift the depth of field to run parallel to the wall, so that all of the wall is in focus. The same thing can be done with landscapes, where a nearby chair in the bottom of the frame can be in focus along with the distant hills in the top of the frame. Lens and film plane movements offer controls that are unheard of with fixed lens cameras.

Rule of thumb:

Use front standard (lens) to control plane of focus.

Use rear standard (film plane) to control perspective.

Zero Position: (Normal Position)

á All movement are set as though it were a rigid bodied camera.

á Front and Rear standards are parallel.

á Front and Rear standards are at a 90 angle to the rail.

á The rear of the Lens is pointed straight at the ground glass.

Controlling Perspective: Rear movements:

Rise and Fall: This is the vertical travel of the standard. Rise means

that the standard can go above neutral position; fall means the standard can drop below neutral position. Generally used for cropping or positioning an image in camera without moving the camera location.. For instance, if photographing a tall building whose top is cut off, the front standard can be raised (or the rear standard lowered) until the top of the image appears (that is, if the image circle is big enough to allow it.). This is a valuable capability because it doesn't alter the perspective the way tilting the camera upward would.

Shift: This is the horizontal travel of the standard--shift left and shift right.

Generally used for cropping or positioning an image in camera without moving the camera location on the Horizontal Axis.

Keystone effect:

Photographing a tall building with a 35mm camera, the building, having vertical, parallel sides, will appear to in the photograph to be narrower at the top. This effect is known as the Keystone effect. The top of the building appears smaller than the bottom because it is farther from the lens than the top. To avoid the keystone effect with your view camera, you cab tilt, or incline, the back.

Rear Movements: Perspective:

Back Tilt: This is when the plane of the standard is moved off vertical. The rear standard tilt makes the film plane point upward or downward. When you do, one end or edge of the film ends up closer to the lens than the other. The cone of light projected rearward by the lens gets larger as it moves away from the lens. When you incline the film plane, the image on the part of the film farther from the lens becomes larger than the part closer to the lens. The tilt will diminish the appearance of convergence toward that side of the image.

Back Swing:

While the tilt controls vertical convergence, back swing affects convergence for horizontal lines. This is when the plane of the standard is turned. A lens or film plane can be swung to the right or the left. The swing movement is most useful when your access to a desired vantage point is limited.

Back Shift: Rising, falling, and lateral shifts- do not alter the perspective but alter the view. Most view camera lenses project an image larger than the film. Shifting the back of the camera side to side and up and down allows you to select the field of view.

Front Movements: Plane of Focus:

Angular movements of the film plane (rear standards). Perspective cannot be changed by moving the front standard.

The Scheimpflug Principle:

When the lens and the film planes are not parallel to each other, an unusual set of optical conditions exists in which the plane of focus cuts at an angle through the image. The principle states that when the lens plane and film plane are not parallel neither will be parallel to the plane of focus.

Front Tilt:

Tilting the front element will move the plane of focus. Tilting the top of the front element away from the film plane moves the plane of focus toward your feet. With the back vertical and the lens tilted foreword, the surface of the floor will be in focus.

Front Swing:

Swinging the front element moves the plane of focus on a diagonal from the left or the right.

Front Shift: Shifting the front does the same as shifting the rear.

Depth of Field and The Scheimpflug Principle:

The behavior of the depth of field is altered by the Scheimpflug principle. Depth of field still is increased by smaller apertures and greater object distances and still surrounds the plane of focus. Since all parts of the plane of focus are not at the same distance from the lens, however, the depth of field is not the same in all parts of the image. Depth of field increases as the plane of focus recedes from the camera.

Bellows Extension Factor

The brightness of light falls off rapidly over distance. Most cameras have

lenses that are fixed into position, and the distance the light travels from

the lens aperture to the film plane is short. On a view camera, the lens can

get moved out quite a distance from the film. The closer the focus point of

the subject is to the camera, the farther out the lens is from the film.

When the lens is focused at infinity, it's relatively close to the film.

As the distance between the lens aperture and the film grows, light falloff

becomes more of a concern, and after a point it has to be compensated. This

is called either bellows extension factor or exposure factor.

The point where the lens distance becomes important is when the focus point

is less than ten times the focal length of the lens. For example, a 6-inch

lens requires the bellows extension factor added in when focusing on a

subject less than 60 inches (5 feet) away.

There are a variety of calculators and rulers that can be used, and there

are various mathematical formulae. Here is one of the simple ones:

Exposure factor = (v/f) squared

where v = the distance from the lens to the film plane (the bellows draw)

f = focal length of the lens

Here it is in action. You meter the subject and you the meter reads 1/125th

at f22. You're using a 6-inch lens and your bellows are racked out 8 1/2

inches.

(v/f) squared = (8.5/6) squared, which is 1.417 squared, which is around 2.

In which case you would either drop the shutter speed to 1/60th or open the

aperture to f16.

What You need:

Camera.

Lens. Large format lenses are lens/shutter combinations that are

mounted onto a lensboard and placed on the front standard. The lenses

are longer than those used on 35mm--a normal lens for 35mm film is

50mm--but a lens for a 4x5 is around 150mm. (Note: Older large format

lenses are often measured in inches rather than metric.

For a close approximation, consider 1 inch to equal 25mm.

Thus a 5 1/2-inch lens is about 135mm.) Also, they have to be able to

create a image that's wider than the negative to allow for the movements.

Film holders. Sheet film has to be held in place by a film holder.

Typically these are little light-tight boxes with removable dark

slides. You load the film into the holders in the dark and put the dark

slide in place. This makes them light-tight. You then put the holder

into the camera back, remove the darkslide, and expose the film. New

film holders are around $12 to $15 each for (4x5 holders. More for the

bigger formats). Used depends on their condition (check them before you

buy) and how desperate the seller is to offload them.

Heavy-duty Tripod. View cameras tend to be large and heavy, and they

require large and sturdy tripods. Typical 35mm camera tripods won't be

good enough-- the center of gravity will be so high that it will be

easy to tip the camera over.

Exposure meter. Since almost all small cameras come with meters, more

and more photographers manage to get through life without a hand meter.

Large format cameras usually don't come with meters, so you'll either

have to get a hand-held meter or use another camera's onboard meter.

Focusing Cloth. Most view cameras are focused by looking at the image

on a ground glass on the film plane. It's too difficult to view the

image with a lot of ambient light, so you'll need a dark cloth to drape

over the back of the camera in order to focus the image. Some cameras

allow for an optional viewing hood.

Loupe: It is often easier and more convenient to focus your image using a loupe.

Taking the Photograph:

1. Put Camera back into Zero position and lock down all controls.

2. Set Aperture at its widest opening.

3. Open the shutter:

á using press-focus lever

á cocking the shutter and releasing on T

á cocking the shutter and releasing on B using cable release to hold shutter open

4. Cover your head and the rear standard with the darkcloth.

5. Look at the image that appears upside down.

6. Loosen the focus lock on the rear standard. (Good habit to get into for close up work)

á Focus the image by rocking the rear standard focus knob back and forth past the point where it looks focused.

á Make sure you CANT see the front rail.!!

7. Make any camera movements.

8. Double check everything is locked down.

9. Tighten focus lock.

10. Select your aperture by stopping down until you get the depth of field you want (not what the meter tells you to, You can adjust the shutter speed to compensate later)

11. Close the shutter

12. Meter your scene

13. Set the aperture

14. Cock the shutter.

15. Insert sheet film holder.

16. Pull the dark slide.

17. Release shutter.

18. Flip Dark slide (So that the black side is towards the front)

19. Replace dark slide.

20. Record the number of the film holder and any data you may need for using the Zone system.

21. Start all over again.

.	Digital Photography Notes
.	Studio and Large Format Basics

		What is large format? Cameras are often divided into groups by the general size of the film that they accept. Large format cameras usually use sheet film that is 4" x 5" or larger (though the cameras can be modified to take smaller films). Medium format cameras generally take large roll films, like 120. Miniature cameras (you don't hear that term much anymore) take 35mm. What is a large format camera? Large format cameras tend to be view cameras, which is itself a generic term. View cameras are generally configured to have a rail or a flat bed running horizontally. There is a front standard where the lens is attached. There is a rear standard that holds the ground glass (for focusing) and the film. In between the standards is a light-tight bellows or bag. The image is focused by changing the distance between the two standards. The standards may also have movements that allow them to tilt or swing relative to each other. These movements allow the image to manipulated in camera for various effects. The Advantages: Image control. Large format cameras have moveable lenses and film planes, which allow a lot of optical effects that are not possible with cameras where the film plane and lens is fixed into a permanent position. Depth of field can be manipulated in more ways. Image perspective can be altered. And views can be framed in camera (to some extent) without moving the camera position. Minimization of grain and enlargement. Smaller formats have to be magnified much more than large formats to get the same print size. Since magnification shows grain, resolving power limitations, and defects on the negative, images that are magnified less tend to look sharper, smoother, and cleaner. Very large formats (such as 8x10) can be directly contact printed into large photographs with no magnification at all. The disadvantages: Expense. Just about anything that has to do with large format is going to cost more than smaller formats. The lenses are more. The cameras are more. The film is more. The enlargers are much more. Time. Large format cameras and techniques are not honed for speed. Large format cameras require tripods, careful focusing, and adjustment of the camera movements to obtain a desired effect. Kinds of view cameras Field cameras are the typical and classical view camera. A field camera is generally intended to be used outdoors. They are often designed to be rugged, lightweight, and compact. They usually have flat beds on the bottom that are hinged to the back (rear standard), which gives a very sturdy platform. They usually have limited or moderate movements and the flat bed folds up to protect the front. Typical field cameras include offerings by Zone VI, the Toyo-field 45AII, and the Horseman 45FA. Studio cameras, often also known as monorail or technical cameras, tend to be designed to look like an optical bench. They usually have one rail (hence monorail that runs horizontally with the front and rear standards attached to it so that they can slide along the rail's length. The rail is mounted on a tripod or equivalent support. The front standard, rear standard, and the bellows tend to be detachable and modular, allowing interchangeability with other standards or accessories (such as extra-long bellows, bags, larger or smaller backs, etc.). They also often have their movements marked and graduated so that the camera's position can be recorded and duplicated. Popular studio cameras include offerings by Sinar, Calumet, Toyo and Horseman. Press cameras are fairly rare today--the name derives from large format cameras used by press (newspaper) photographers. They tend to have limited or no movements. They tend to be compact, lightweight, and rugged. The big differences between press cameras and traditional field cameras are that press cameras are meant be hand holdable, are meant to be focused with a viewfinder instead of a ground glass back, and have limited or no movements. Sizes of film Sheet film is typically measured in inches. The most common (and smallest) size is 4x5. The two other common sizes are 5x7 and 8x10. There are also less common sizes available, such as 11x14 (which many people like because it contact prints a large photo). Descriptions of the Camera. á The rail: á Front and Rear Standards: á Bellows: á Spring Back: á Ground Glass: á Lenseboard: á Lens and Shutter: á Film Plane: á Lens Plane: Camera Movements Movements allow the front (lens) and rear (film) standards to be adjusted relative to each other, which allow for special optical effects. For the purposes of this discussion, I'll define neutral or normal position as when the lens axis (an imaginary line that runs through the optical center of the lens) is perpendicular to and centered on the film plane. This is the configuration almost all cameras normally have. Most cameras are fixed in this position. View cameras, however, can change this. Camera Movements: Increases your ability to control: á Perspective: relative sizes of objects in an image. á Plane of focus: the plane in front of the lens in which all points are in focus. Perspective: Have you ever looked at a photograph of a skyscraper (or any tall building) and it looked like it was collapsing because the walls were converging? This is called keystoneing. It usually comes from tilting a camera upward--parallel lines converge and the perspective is loused up. Large format cameras can correct this--if the camera is pointed upward, the standards can be tilted so that the parallels no longer converge. This is invaluable in architectural photography. Focus control: With a fixed lens camera, depth of field is simply the area in focus from a certain minimum distance to a certain maximum distance. This area of focus is actually a three-dimensional space--and this space's position can be altered by the movement of the camera standards. A classic example is a photograph of a wall that runs diagonally from your camera position. Suppose that it is impossible, with a fixed lens camera, to get the whole wall in focus because the depth of field just does not get large enough to cover. A view camera can shift the depth of field to run parallel to the wall, so that all of the wall is in focus. The same thing can be done with landscapes, where a nearby chair in the bottom of the frame can be in focus along with the distant hills in the top of the frame. Lens and film plane movements offer controls that are unheard of with fixed lens cameras. Rule of thumb: Use front standard (lens) to control plane of focus. Use rear standard (film plane) to control perspective. Zero Position: (Normal Position) á All movement are set as though it were a rigid bodied camera. á Front and Rear standards are parallel. á Front and Rear standards are at a 90 angle to the rail. á The rear of the Lens is pointed straight at the ground glass. Controlling Perspective: Rear movements: Rise and Fall: This is the vertical travel of the standard. Rise means that the standard can go above neutral position; fall means the standard can drop below neutral position. Generally used for cropping or positioning an image in camera without moving the camera location.. For instance, if photographing a tall building whose top is cut off, the front standard can be raised (or the rear standard lowered) until the top of the image appears (that is, if the image circle is big enough to allow it.). This is a valuable capability because it doesn't alter the perspective the way tilting the camera upward would. Shift: This is the horizontal travel of the standard--shift left and shift right. Generally used for cropping or positioning an image in camera without moving the camera location on the Horizontal Axis. Keystone effect: Photographing a tall building with a 35mm camera, the building, having vertical, parallel sides, will appear to in the photograph to be narrower at the top. This effect is known as the Keystone effect. The top of the building appears smaller than the bottom because it is farther from the lens than the top. To avoid the keystone effect with your view camera, you cab tilt, or incline, the back. Rear Movements: Perspective: Back Tilt: This is when the plane of the standard is moved off vertical. The rear standard tilt makes the film plane point upward or downward. When you do, one end or edge of the film ends up closer to the lens than the other. The cone of light projected rearward by the lens gets larger as it moves away from the lens. When you incline the film plane, the image on the part of the film farther from the lens becomes larger than the part closer to the lens. The tilt will diminish the appearance of convergence toward that side of the image. Back Swing: While the tilt controls vertical convergence, back swing affects convergence for horizontal lines. This is when the plane of the standard is turned. A lens or film plane can be swung to the right or the left. The swing movement is most useful when your access to a desired vantage point is limited. Back Shift: Rising, falling, and lateral shifts- do not alter the perspective but alter the view. Most view camera lenses project an image larger than the film. Shifting the back of the camera side to side and up and down allows you to select the field of view. Front Movements: Plane of Focus: Angular movements of the film plane (rear standards). Perspective cannot be changed by moving the front standard. The Scheimpflug Principle: When the lens and the film planes are not parallel to each other, an unusual set of optical conditions exists in which the plane of focus cuts at an angle through the image. The principle states that when the lens plane and film plane are not parallel neither will be parallel to the plane of focus. Front Tilt: Tilting the front element will move the plane of focus. Tilting the top of the front element away from the film plane moves the plane of focus toward your feet. With the back vertical and the lens tilted foreword, the surface of the floor will be in focus. Front Swing: Swinging the front element moves the plane of focus on a diagonal from the left or the right. Front Shift: Shifting the front does the same as shifting the rear. Depth of Field and The Scheimpflug Principle: The behavior of the depth of field is altered by the Scheimpflug principle. Depth of field still is increased by smaller apertures and greater object distances and still surrounds the plane of focus. Since all parts of the plane of focus are not at the same distance from the lens, however, the depth of field is not the same in all parts of the image. Depth of field increases as the plane of focus recedes from the camera. Bellows Extension Factor The brightness of light falls off rapidly over distance. Most cameras have lenses that are fixed into position, and the distance the light travels from the lens aperture to the film plane is short. On a view camera, the lens can get moved out quite a distance from the film. The closer the focus point of the subject is to the camera, the farther out the lens is from the film. When the lens is focused at infinity, it's relatively close to the film. As the distance between the lens aperture and the film grows, light falloff becomes more of a concern, and after a point it has to be compensated. This is called either bellows extension factor or exposure factor. The point where the lens distance becomes important is when the focus point is less than ten times the focal length of the lens. For example, a 6-inch lens requires the bellows extension factor added in when focusing on a subject less than 60 inches (5 feet) away. There are a variety of calculators and rulers that can be used, and there are various mathematical formulae. Here is one of the simple ones: Exposure factor = (v/f) squared where v = the distance from the lens to the film plane (the bellows draw) f = focal length of the lens Here it is in action. You meter the subject and you the meter reads 1/125th at f22. You're using a 6-inch lens and your bellows are racked out 8 1/2 inches. (v/f) squared = (8.5/6) squared, which is 1.417 squared, which is around 2. In which case you would either drop the shutter speed to 1/60th or open the aperture to f16. What You need: Camera. Lens. Large format lenses are lens/shutter combinations that are mounted onto a lensboard and placed on the front standard. The lenses are longer than those used on 35mm--a normal lens for 35mm film is 50mm--but a lens for a 4x5 is around 150mm. (Note: Older large format lenses are often measured in inches rather than metric. For a close approximation, consider 1 inch to equal 25mm. Thus a 5 1/2-inch lens is about 135mm.) Also, they have to be able to create a image that's wider than the negative to allow for the movements. Film holders. Sheet film has to be held in place by a film holder. Typically these are little light-tight boxes with removable dark slides. You load the film into the holders in the dark and put the dark slide in place. This makes them light-tight. You then put the holder into the camera back, remove the darkslide, and expose the film. New film holders are around $12 to $15 each for (4x5 holders. More for the bigger formats). Used depends on their condition (check them before you buy) and how desperate the seller is to offload them. Heavy-duty Tripod. View cameras tend to be large and heavy, and they require large and sturdy tripods. Typical 35mm camera tripods won't be good enough-- the center of gravity will be so high that it will be easy to tip the camera over. Exposure meter. Since almost all small cameras come with meters, more and more photographers manage to get through life without a hand meter. Large format cameras usually don't come with meters, so you'll either have to get a hand-held meter or use another camera's onboard meter. Focusing Cloth. Most view cameras are focused by looking at the image on a ground glass on the film plane. It's too difficult to view the image with a lot of ambient light, so you'll need a dark cloth to drape over the back of the camera in order to focus the image. Some cameras allow for an optional viewing hood. Loupe: It is often easier and more convenient to focus your image using a loupe. Taking the Photograph: 1. Put Camera back into Zero position and lock down all controls. 2. Set Aperture at its widest opening. 3. Open the shutter: á using *press-focus lever* á cocking the shutter and releasing on T á cocking the shutter and releasing on B using cable release to hold shutter open 4. Cover your head and the rear standard with the darkcloth. 5. Look at the image that appears upside down. 6. Loosen the focus lock on the rear standard. (Good habit to get into for close up work) á Focus the image by rocking the rear standard focus knob back and forth past the point where it looks focused. á Make sure you CANT see the front rail.!! 7. Make any camera movements. 8. Double check everything is locked down. 9. Tighten focus lock. 10. Select your aperture by stopping down until you get the depth of field you want (not what the meter tells you to, You can adjust the shutter speed to compensate later) 11. Close the shutter 12. Meter your scene 13. Set the aperture 14. Cock the shutter. 15. Insert sheet film holder. 16. Pull the dark slide. 17. Release shutter. 18. Flip Dark slide (So that the black side is towards the front) 19. Replace dark slide. 20. Record the number of the film holder and any data you may need for using the Zone system. 21. Start all over again.