Large Format
From 1991 to 2005, my main camera was always a large format camera. Also know as a view camera, a large format camera makes images on individual sheets of film (as opposed to 35mm and medium cameras, which use film formed into a long roll, with multiple exposures made on the roll before it is fully exposed).
The main reasons for using large format cameras (also called view cameras) is the film size and the camera movements. 
Most people who use large format cameras use 4"x5” cameras - these have a good balance between size, flexibility and expense. I used a 4"x5” view camera consistantly from 1991 to 2001. Between 2001 and 2005, I worked exclusively with an 8"x10” large format camera.
The primary difference between a large format camera and most other camera systems is the flexibilities that the large format offers. Because the lenses are attached to the body with a flexible bellows, you can change the alignment of the lens and film to control both the shape of your subject and how the plane of focus moves across the subject.
The final advantage of large format cameras is that each image is made on a separate sheet of film, so each photograph can be separately processed and tailored to the needs of each exposure. It can also mean you can carry a variety of emulsions and types of film (colour, B+W, infra-red) without having to use a whole roll of each before processing the results.
4"x5” View Cameras
My first view camera was a Busch Pressman D, purchased in 1991. This camera worked well as an introduction to large format, and was a real workhorse, being a metal camera. I used this camera for much of my fine art work until 1994, when I purchased a Nikkor 210mm lens, only to discover it would not fit the camera. As a result, I bought a used 4"x5” Wista, a light wooden field camera with more movements then the Busch Pressman and almost half the weight. At the same time as I was focusing on working with the 4"x5” format, I purchased a used Burke and James 8"x10” camera, to start exploring the possibilities of a different format.
From 1994-1998, my main camera was the Wista; a light, flexible camera, this served to help me create many of the images that are the foundation of my current work. When, in 1998, this camera fell victim to an accident in a river, I had to replace it, upgrading it to an American-made Wisner 4x5 Traditional. The reason for selecting the Wisner was manifold - it had more bellows extension (21” as opposed to the 12” on the Wisner) which helps when working with longer focal length lenses and, as I was using more and more wide-angle lenses, the ability to use a bag-bellows on the Wisner was also particularly attractive. The bag bellows permits more flexibility when using wide angle lenses - the movements that are often needed with these lenses can kink bellows, or even be totally restricted by them, where the bag bellows permits almost total freedom of movement.
8"x10” View Cameras
After working with 4x5 for a decade, I started questioning if 4"x5” was the best format for my work in 2000. I started working with large format in 1991 as a reaction against the “machine-gun” approach of smaller formats. The larger negative (53 times larger than a 35mm negative) and cameras demanded more effort in the field and, in turn, placed more focus on the technical elements of photography, pushing up the exertion (both mentally and physically) required to make an image. By 2000, however,I was frequently making 30-60 images a day, where I had initially focused upon 12-18 images a day. I began reconsidering working with 8"x10” cameras, and in 2001 made the decision to purchase a 8"x10” Toyo 810G, to see if my hunch that this larger, more demanding format would better suit my workflow.
It was the Cassandra Portfolio that proved to me that stepping up to 8"x10” as my main camera was a positive evolution. 
Over the two weeks of working with Cassandra, I worked back and forth between 4"x5” and 8"x10”, and the over all conclusion was that the larger format worked better for my way of seeing; the pleasure of composing on the larger ground-glass, the extra discipline required when there can only be 12-18 images made a session, and the slowing down of the process that becomes inevitable when working with such a large camera all helped focus my work more clearly, and lead to very striking results. By the spring of 2002, I had sold all my 4"x5” equipment, and had begun refining my Toyo 8x10 equipment to better reflect my needs and desires as a photographer. I used the Toyo 810G for three years, making a little over 1200 images.
At the end of 2003, I purchased a Zone VI Ultralight 8"x10” camera to replace the Toyo 810G. The reason for the change to the Zone VI camera was weight - as a wooden field camera it weighs less than 5 kg - half the weight of the Toyo. Initially I had planned to keep the Toyo as a studio camera, but common sense prevailed, and I sold the Toyo 810G in early 2004. With the change to the Zone VI Ultralight, I finally managed to get the three lens system I had longed for; a 150mm, a 300mm, and a 450mm lens. I carried carry 10 film holders with me, permitting me to expose 20 sheets of film before reloading (which is not the easiest thing to do in the field).
Ultra-Large Format View Cameras
Large format cameras is not limited to 4"x5” and 8"x10”; once there were more then a dozen dedicated formats, but most of these have since become either relegated to history, or the focus of a very small number of keen users. The camera formats that really engage me are the ultra-large formats - these come in a variety of different sizes, but the most common are 11"x14”, 7"x17”, 8"x20”, 12"x20”, 16"x20” and 20"x24”. These cameras are designed to be used for contact prints (the prints are the same size as the negatives), and as such, have some limitations, in regards to what can be done with the images they make. The real attraction of ultra-large format cameras are the demands they place on the working process and the incredible detail that they can record.
In 2001, I worked with a Korona 12x20 camera, and over the summer made eighteen images with the camera; the possibilities were somewhat limited by the fact the camera only came with one lens, but after making the images, I knew that this was an approach I could get used to in time. Unfortunately, because of the prohibitive cost of ULF (ultra-large format) photography, which runs as much as $17 per photograph, this was my only experience with such cameras.
Lenses
A major advantage of a large format camera is the ability to use whatever lens you wish to place on it. Unlike 35mm cameras, you are not limited to lenses that are ,manufactured specifically for the body. As long as the camera body can physically accommodate the lens, and the lens has a shutter, or some other way to control the length of the exposure, any large format lens can fit on any camera. I have occasionally used lenses that are over a century old!
Most view camera lenses contain leaf-shutters, which have the advantage of maintaining a flash sync at any speed. Some press cameras, like the Speed Graphic, use focal-plane shutters (similar to modern 35mm SLRs), while a few older models (or expensive contemporary ones) have separate leaf-shutters behind the lenses. This helps keep exposure times consistent between different lenses.
My final (and ideal) lens set consisted of three modern lenses; a 150mm f/5.6 Super-Symmar XL (equal to about a 24mm lens on a 35mm camera), a 300mm f/5.6 Fujinon (equal to about a 50mm lens on a 35mm camera), a 450mm f/9 Nikkor (equal to about a 75mm lens on a 35mm camera). This lens set has been a recent addition (fall 2003), and is as close to an ideal as I have ever been able to assemble. The spacing of these lenses in terms of focal length (150, 300, 450) means they are all evenly stepped, or separated, so it is easier to predict which lens is called for, and more importantly, there is no debate as to which lens would be more appropriate for an image.
Lenses I have used in the past with 8x10 include: 10” Kodak Commercial Ektar, 12” Kodak Commercial Ektar, 159mm f/9.5 Wollensak lens, 240mm f/5.6 Schneider Symmar, 360mm f/6.3 Schneider Symmar-S, 14 3/4” f/7.7 Optar, and a 19” f/7.7 Caltar. All these lenses had good to great performance, but for one reason or another, were eventually sold to purchase other lenses.
Lenses I have used in the past with 4x5 include: 150mm f/5.6 Schneider Symmar, a Nikon-W 210mm f/5.6, 90mm f/8 Schneider Super-Angulon , a 75mm f/4.5 Rodenstock, and a 65mm f/8 Schneider Super-Angulon. I also used the 12” Kodak Commercial Ektar on my 4"x5” occasionally.
Lens Angle of View
Below is the same image made from the same position with three lenses (simulated).
A wide angle lens helps describe space, and shows a broader perspective then the eye usually see - often wide angle lenses are used in small or cramped spaces. Some distortion can be introduced by extreme wide angle lenses.
On a 4"x5” camera, any lens from 135mm down is considered a wide lens. Over the years I worked with 4"x5” cameras, I used 65mm, 75mm, 90mm and 135mm lenses, with my favourite being the 75mm lens, which was just fabulous to work with. With the 8"x10” camera, a 150mm lens gives the same angle of view, with more than enough coverage to permit relatively extreme movements.
A normal lens gives approximately the same angle of view as the human eye, and is often used when a wider or longer perspective aren’t appropriate. Normal lenses do not exaggerate or minimize perspective or proportions, but are often chooses for their natural look.
On a 4"x5” camera, the normal les is considered to be 150mm, while on an 8"x10 camera, a 300mm lens is the normal. While these lenses are seldom used (they tend to be less dramatic in the results than either a wide or long lens), there are always images that couldn’t be made with any other lens, so it is important to always have one.
A long lens (sometimes incorrectly referred to as telephoto lenses or zoom lenses) narrows the camera’s angle of view, bringing far objects closer to the camera. It can be used to enlarge far objects, and to compress space in an image.
A 450mm lens shows 50% less then a 300mm lens, and nine-times less then the 150mm lens. This is the start of long lenses for an 8"x10” camera, but it does provide a different perspective from a normal or wide lens. On a 35mm camera, a lens longer then 50mm is considered a long lens.
Camera Movements
Facilitated by the lens being connected to the camera back by a flexible bellows, camera movements allow a photographer to shift the film and lens position, change the alignment of the film and plane, and alter the proportion of images within the frame. 
All this flexibility gives the photographer incredible control over depth of field, focus points, perspective, proportion, and image shape.
A good example of how the ability to move the lens independent of the film is show with the image of the church to the right. The right image is an uncorrected photograph, where the camera is tilted up to include the church steeple. The left image used a rise movement to move the lens up, so the top of the steeple was included without moving the camera off level.
One of the most important things to understand with lenses is that different focal length can give the same image result on different film formats, if the focal lengths are proportional to the change in film size.
All that said, the wide, normal and telephoto lenses will give approximately the same viewpoint on each of camera systems.