Photography Basics

Brief History Forerunner to the camera was the camera obscura. The camera obscura is an instrument consisting of a darkened chamber or box, into which light is admitted through a double convex lens, forming an image of external objects on a surface of paper or glass, etc., placed at the focus of the lens.

Oldest Surviving Photograph The photograph was made using a camera obscura and a sheet of pewter coated with bitumen of Judea, a material that when exposed to light, hardened permanently. This first photograph was captured during an eight hour exposure, taking so much time that the sun passed overhead and thus illuminating both sides of the courtyard.camera obscura

The Daguerreotype Daguerre invented first practical photographic process in 1837 –Copper plates coated with silver and fumed with iodine = light-sensitive silver iodide –Expose, “develop” with mercury, and fix –One-of-a-kind, silvery, monochromatic image Daguerreotypes introduced to the public in 1839 –“Painting is dead!”

William Talbot and The Photogram -Talbot (English) used paper sensitized with silver chloride -Photogram: lay objects on paper and expose to light -Invented negative-positive photographic system Laid another sheet of sensitized paper against negative image- Reproducible photographs

The Collodion Wet-Plate Process 8fQOdvDshttp:// 8fQOdvDs The process involves: bromide, iodide or chloride salts dissolved in collodion, which is a solution of pyroxylin in alcohol and ether. This mixture was poured onto a cleaned glass plate, and allowed to sit for a few seconds. The plate was then placed into a solution of silver nitrate and water, which would convert the iodide, bromide or chloride salts to silver iodide, bromide or chloride, respectively. Once this reaction was complete, the plate was removed from the silver nitrate solution, and exposed in a camera while still wet. It was developed with a solution of iron sulfate, acetic acid and alcohol.collodionpyroxylin

More Innovation Flexible film base –George Eastman’s Kodak, 1888, used roll film –Base was opaque, so emulsion had to be transferred to glass plate –Return entire camera for developing –1889: transparent-based film (Eastman and others) Photo take with Kodak camera

Viewfinder/Rangefinder Cameras View through eyepiece with simple lens Parallax error: viewfinder isn’t in same position as camera lens, so view is slightly different

Twin-Lens Reflex Cameras One lens to film, the other mirrored to eye Image focused on ground glass

View Cameras Direct viewing: ground glass is exactly where the film will be Large-format Usually uses sheet film

Single-Lens Reflex Cameras View the actual image that will fall on the film Image focused on ground glass

Optical Components of an SLR Camera A cross-section of the optical components of a SLR camera shows how the light passes through the lens assembly (1), is reflected by the mirror (2) and is projected on the matte focusing screen (5). By a condensing lens (6) and internal reflections in the roof pentaprism (7) the image appears in the eyepiece (8). When an image is taken, the mirror moves upwards from its critical 45 degree angle in the direction of the arrow, the focal plane shutter (3) opens, and the image is projected onto the film or sensor (4) in exactly the same manner as on the focusing screen. filmsensor

Locating Camera Parts

35 mm Manual Camera Two controls alter film exposure: –Aperture measured in f- stops Larger f-stop = less exposure Aperture control ring set at f/8

35 mm Manual Camera Two controls alter film exposure: –Shutter speed Measured in seconds Faster speed = less exposure Shutter speed dial set for 1/125 second

Leaf Shutters Lightweight and quiet Synchronize with flash Difficult to achieve fast shutter speeds

Focal Plane Shutters Heavier & noisier Convenient with TTL systems Faster shutter speeds

A Procedure for Taking Photographs Load the film into the camera Develop ideas for photographs Frame and compose your photograph Evaluate the light on your subject Focus the camera Expose the film Rewind the film and remove it from the camera Process and print the exposed film

Load the film into the camera Open the back Insert film—don’t expose it to light! Insert film leader in spindle Advance film until it’s securely wrapped Close and latch camera back

Frame and Compose Look through viewfinder Move your subject as needed Make sure back- ground doesn’t distract Remember you can turn camera on end

Film Light-Sensitive Materials Photosensitive = light-sensitive Silver salts (silver halide crystals) turn dark when exposed to light Small amount of light on silver salts produces latent image Developing process increases density of latent image

Light-Sensitive Materials Since light turns silver salts dark, the result is a negative image Printing reverses the process to show a positive image Support of the silver salt is the base: transparent for film, paper for prints

Structure of Black-and-White Films Simple silver salts give a monochrome (b/w) image Silver salts combined with gelatin form an emulsion that adheres to base Sensitivity dyes in the emulsion increase the film’s response to some colors Choose films with the same emulsion batch number if you need consistency from roll to roll

Structure of Black-and-White Films 1 Scratch-resistant coating 2 Emulsion 3 Adhesive 4 Base 5 Adhesive 6 Antihalation backing

Film Formats and Packaging Format size = size of image produced on film APS cartridge 35mm cassette

Film Formats 120 or 220 roll film Sheet film (4 × 5 or larger)

Film Storage Protect your film from: –High humidity: store in moisture-proof container –High temperature: store in refrigerator or freezer Bring film to room temperature before using! –Exposure to light: load and unload in shadow –Exposure to X-rays: in airports, ask for hand inspection or use lead-foil bags –Age: film box is dated

Film Handling Film is sensitive to scratching and fingerprints Keep camera clean Use slow, steady motion when advancing or rewinding film

Camera and Lens Care and Maintenance Avoid rough handling Protect lens from fingerprints and scratches Protect camera and lens from moisture, humidity, heat, dirt, direct sunlight Never force controls

Camera and Lens Care and Maintenance Battery –Check regularly and replace if necessary –Keep contacts clean Periodic service center maintenance Cleaning –Clean carefully with soft cloths and brushes –Never clean focal plane shutter or single-lens reflex camera mirror –Clean lens only when necessary with lens brush or compressed air