Lens

Larry Sultan

FILE FORMAT Jpeg (.jpg) > compresses > opening it = changing it, saving it = degrading image. TiFF (.tif) > universal format > high quality good for printing LOSSLESS PSD (.psd) > Can opened & edit only in photoshop Camera Raw (.nef, .crw, .pef & more) = the most direct representation, no data lost DNG (.dng) just like camera raw but universal GIF (.gif) > small web file, good for flat color, drawing EPS (eps) > good for photo & text, use in publishing BMP (.bmp) windows & PICT (.pct) mac > these are platform specific. PNG (.png) = adobe fireworks > lossless, use for web

The focal length of a lens is defined as the distance in mm from the optical center of the lens to the focal point, which is located on the sensor or film if the subject (at infinity) is "in focus". The camera lens projects part of the scene onto the film or sensor.

Focal length controls -magnification -the size of image formed by the lens - the angle of view The longer lens = the greater size

Normal focal length lens (or standard focal length lens), approximates the impression human vision gives.

Henry Cartier-Bresson Normal focal length

A lens that is normal focal length for one camera can be a Long focal length for another. Film or sensor size determines What will be a normal focal length. The larger the sensor size =The longer the focal length of a normal lens for that format

Long focal length lens

-Greater image magnification -narrower angle of view -good for zooming -distance object -good for portraiture (prevent distortion when Shooting up close) -telephoto or tele

Lou Jones, 2006 Winter Olympics - Torino, Italy

Short focal length lens or wide-angle lens

-Increases the angle of view -show more of a scene from the same position -good depth of field (good When you are on the run) -show an apparent distortion of perspective

David Muench

Zoom lenses combine a range of focal lengths into one lens. Ex. 28-105 mm = 28mm, 50mm, 85mm, & 105mm

Zoom lenses can be very useful!

Macro Lens is useful for extremely close shots

Fisheye lens = widest of wide-angle view

Fisheye lens distort space

Focusing your lens Think! What is the most important part of the scene to be sharp? Focus critically when shooting image with shallow depth of field Practice follow focus -- start with slow moving subject then practice on faster things

Remember Shutter speed and aperture also control the sharpness. Additional options Zone Focus = set depth of field in advance of shooting so you can shoot quickly without refocusing every shot. (need lens with DOF scale) Focusing on the hyperfocal distance will give you the maximum (most possible) depth of field every time. (need lens with DOF scale)

Zone focus

Helen Levitt

Helen Levitt, New York, 1971

Jan Imberi (hyperfocal distance focus)

John Pfahl

John Pfahl

what is the most important part of the scene to be focus

Or what is the most important part of the scene to be un-focus

Sally Mann, The Perfect Tomato, 1990.

Perspective = how we see or judge depth in 2D. Perspective can be controlled by adjusting lens to subject distance

Perspective is not depth of field. Depth of field is the area from near to far in a scene that is acceptably sharp in a photograph.

Andreas Feininger, New York, NY, US

Long focal length lens = telephoto effect = exaggerated perspective

Short focal length lens = exaggerated perspective

Jan Dibbets

Jan Dibbets

Remember! The smaller the aperture = the greater depth of field The shorter the focal length of the lens = the greater depth of field The greater the distance from the subject = the greater depth of field

The sizes of the aperture openings are determined so that at a given f-stop number the same amount of light reaches the film/image sensor.

F- stop = lens focal length Aperture diameter Ex. 100mm lens 25mm lens opening

=

F/4

200mm lens 50mm lens opening

=

F/4

Instead of film, digital cameras use a solid-state device called an image sensor. In some digital cameras the image sensor is a charge-coupled device (CCD), while in others it's a CMOS sensor.Both types can give very good results.

Digital photographs are actually mosaics of millions of tiny squares called picture elements— or just pixels. Like the impressionist painters who painted wonderful scenes with small dabs of paint, your computer and printer use these tiny pixels to display or print photographs. To do so, the computer divides the screen or printed page into a grid of pixels. It then uses the values stored in the digital photograph to specify the brightness and color of each pixel in this grid—a form of painting by number.

When capturing an image, the number of pixels used to capture it (sometimes referred to as resolution or pixel count) has a big effect on how large it can be displayed on the screen or printed. At any given size, more pixels add detail and sharpen edges. Because numbers matter so much, the best approach is to shoot using the largest available size. You can always make an image smaller in a photo-editing program, but you can never make it larger while retaining the original quality.

Square pixels are arranged in patterns to form curved lines and edges in a photo. The more pixels used, the smoother these curves will be. Here the same red ball is represented by 4, 12, and then 24 square pixels. As more pixels are added, edges become more refined and the shape becomes more like the original. http://video.nytimes.com/video/2005/12/08/technology/poguesposts/1194817103335/shutterbugs-rejoice.html?scp=2&sq=digital%20camera&st=cse

Exposure = Intensity (aperture) X Time (shutter speed) Exposure is a combination of the intensity (brightness) of Light that reaches the digital sensor of film (brightness is controlled by the size of the aperture) and the length of time The light strike that light sensitive surface (duration is controlled by the shutter speed). YOU ADJUST THE EXPOSURE OF YOUR PICTURES BY CHANGING THE SHUTTER SPEED, APERTURE, OR BOTH Remember 3 types of exposure? Manual Shutter Priority Aperture Priority

Exposure meters average the tones in a scene, Average tone = medium gray =18 percent gray

Remember! Automatic exposure can underexpose Or overexpose your subject. You may have to override it to get the Exposure you want.

Overriding automatic exposure by -go to manual mode -Exposure compensation dial -Backlit button (for backlit scenes)

Tones and Bracketing Remember! For digital camera, Overexposure can lose significant Detail from highlight area that CANNOT be added later.

BEST BET? Bracketing = produces Lighter and darker versions Of the same scene

ISO (International Organization Standardization) number Tells how sensitive a film or sensor is to light The higher the ISO = the less light is required But you pay the price: Increasing the sensitivity of the camera's light sensor (ISO) introduces noise into the photo--random pixels of color. In ordinary conditions, stick with the camera's lowest ISO level, since that'll give you the least digital noise. But when you notice that the camera is recommending a really slow shutter speed crank up the ISO. Just remember to drop it back down to the lower value when you're done. Tip: Your camera may have noise reduction!

Iso 50

Iso 100

Iso 400

Sally Mann

Hiroshi Sugimoto

Tokohiro Sato (long exposure)

Jeff Wall, Passerby, 1996

Tina Modotti

An-My Lê

The Daguerreotype Louis-Jacques-Mandé Daguerre invented the daguerreotype process in France. The invention was announced to the public on August 19, 1839 at a meeting of the French Academy of Sciences in Paris. American photographers quickly capitalized on this new invention, which was capable of capturing a "truthful likeness." Daguerreotypists in major cities invited celebrities and political figures to their studios in the hopes of obtaining a likeness for display in their windows and reception areas. The Process The daguerreotype is a direct-positive process, creating a highly detailed image on a sheet of copper plated with a thin coat of silver without the use of a negative. The process required great care. The silver-plated copper plate had first to be cleaned and polished until the surface looked like a mirror. Next, the plate was sensitized in a closed box over iodine until it took on a yellow-rose appearance. The plate, held in a lightproof holder, was then transferred to the camera. After exposure to light, the plate was developed over hot mercury until an image appeared. To fix the image, the plate was immersed in a solution of sodium thiosulfate or salt and then toned with gold chloride. Exposure times for the earliest daguerreotypes ranged from three to fifteen minutes, making the process nearly impractical for portraiture. Modifications to the sensitization process coupled with the improvement of photographic lenses soon reduced the exposure time to less than a minute.

Mary Todd Lincoln, wife of Abraham Lincoln. Three-quarter length portrait, seated, facing front

http://lcweb2.loc.gov/ammem/daghtml/daghome.html