Archaeological Photography Workshop Field Archaeology ARCH1003

Archaeological Photography Workshop

Field Archaeology ARCH1003

Archaeological Photography Objectives

Photo Documentation (Hester 1997)A comprehensive and technical record of an investigation from beginning to end

Excavation, process of recovering artefacts, sequences, units and profiles, survey finds. It is a historical record

Ethical responsibility of archaeologist to visually record an irreversible process such as excavation or survey. Subsequent analysis or re-analysis of your work in future

Photo Illustration (Hester 1997)To provide images for publication or presentation What are you trying to communicate to the public or in the journal?

Why photograph and illustrate?

Single Lens Reflex (SLR) Camera Features

LensLens apertureFocusing ringAuto AdvanceAperture or AV valueHot shoeShutter speed or TV

(Time Value)

ISO settingShutter releaseFrame counterFocal plane shutterRemote release

socketFilm WindowMirrorPrism

Light

Light is focussed through a lens by refraction (bending of light rays) to form an image behind the lens

To produce a photograph we need:

A light source

An object such as a mirror to reflect the light

A light sensitive medium to record the reflected light (film/digital sensor)

Colour temperature (degrees Kelvin)

Aperture Value

Aperture = f/stop = AV (Pentax camera)

Size of the aperture opening in the lens

A large number (F22) is a small aperture

A small number (F2.8) is a large aperture

To stop down is to reduce the aperture

The f number derives from dividing the focal length (mm) of the lens by the diameter of the aperture

Relationship Between Aperture and Light

Time Value/Shutter Speed

Time Value = shutter speed = TV (Pentax camera)

Length of time the camera shutter opens to expose the film/sensor to the light coming through the lens

1/8 second or slow shutter speed (requires tripod to avoid camera shake)

1/4000 or fast shutter speed (captures water splashing)

Exposure

Exposure is the total amount of light reaching the film calculated from a combination of aperture value (AV) and time value (TV)

Reducing the AV value (or f-stop) from f16 to f22 necessitates doubling the exposure time or TV (time value) for the same exposure result

1/250 second at f22 will give the same exposure result as 1/125 second at f16 (TV reduced but aperture opened up)

Depth of Field

Depth of field is the zone extending in front of and behind the focussed distance within which points will appear to be sharp

The smaller the aperture (AV 22) increases the depth of field

The larger the aperture (AV 5.6) decreases the depth of field

Shorter focal length (wide-angle 28mm) increases depth of field

Longer focal length (telephoto 300mm) decreases depth of field

Focal Length

Light travels in parallel beams and reaches the lens

The distance between the lens and the point at which such light is focussed is the focal length of the lens

It is always expressed in millimetresAn object the same distance away from a long

focal lens will give a larger image than one of short focal length

Standard focal length is 50mm for 35mm camera (negative is 35mm x 24mm)

Angle of View

The angle of view for the human eye is around 45 degrees

Angle of view is the amount of the scene in front of camera taken in by the lens.

A fish eye lens (18mm focal length) will provide 180 degrees angle of view

A telephoto lens (1200mm focal length) will provide 2 degrees

Note: A longer focal length (300mm lens) will decrease the depth of field

Film speed

ISO film speed is the films sensitivity to light rating

The more sensitive the film, the higher the ISO number and the less light required

ISO 6 is a slow, fine grained film and requires a tripod

800 or 1600 ISO is a fast film (newer films not so grainy, used with/without flash)

TMax 3200 can be used with available light at night

Perspective

The apparent distance in the relative sizes of near and far objects

A function of the distance away of the cameraWide angle distortion 28 to 35mm may steepen

the perspective of your trench or structure leading to convergence of lines and aberrations at edge of negative

Standard focal length lens (50mm) or higher will give normal perspective

Telephoto lens (above 50mm) may flatten perspective

Metering

Current Single Lens Reflex (SLRs) cameras have built in metering

Correct Exposure (Pentax) is when the green light is half-way and is changed by adjusting AV/TV values

If positive = overexposedIf negative = underexposedNote: internal meter reads whole scene not just

object unless that fills the frameIncident, reflective, spot metering, grey cards

Camera Handling and Care

Dirt, water, dust, sun can damage cameras and/or precious exposed film

Use bag or waterproof case (e.g. Pelican) for rainy days

Lens tissue for clearer picture. Check the lens!

filters will help protect the lens

Do not over tighten the tripod screw

Batteries may leak if for a long time in the camera

Field Equipment

Scale (range pole and/or centimetre scales)

Additional cameras (black and white, slide and/or colour print, digital)

Photographic proforma or notebook/register

North arrowTripod and remote cable

releaseFlash/Supplementary

Lighting

Film! cards/laptop/burnerBatteriesFiltersSpecial requirements for

digital camerasCamera hood and

waterproof caseReflectors Lens cleaning materialSpecial lenses

General Principles of Archaeological Photography

Technical Photograph descriptive and realistic

Control the lightUse an appropriate scaleA scale should be in the same

plane as the objectViewpoint is critical. Fill the

frame. Use macro lenses/function for small objects

Film/CD media is low cost, while project time is not Exposure is critical

Record on proforma/notebook (Never Later)

Record meaningful information

A changing landscape?Detail, Geology,

construction materials, flora,

Save images to digital archive at highest resolution possible and back up records

Overall Site and Aerial Photographs

The relationship between a site and surroundings is essential. Try to convey a sense of context or environment

Try to take an elevated photograph if possible (wall, ladder, tree, elevating machinery, box

Conventional aerial photographs - planes,

Low-level aerial photographs - booms, balloons, and kites

Photo Illustration

Photo Illustration

Aerial Site OverviewPhoto: David Webb, UK

Critique Photograph

Critique Photograph

Critique Photograph

Critique Photograph

Scale

Scale Position/Use of Negative

Human Scale/Site Context

Scale/Use of Negative/Cleaning

Direct Sunlight/Contrast

Diffuse Light

Overcast Lighting/Scale/Use of Negative

Background Placement, Scale, Glass in Sunlight

Artefact Use Visualization

Finger as Scale

Scale Size/Placement

Scale Placement

IFRAO scale AURA, PO BOX 216, Caufield

South VIC 3162auraweb@hotmail.com

Rock ArtIFRAO scale

Studio Lighting

Studio Lighting