Photography in Archaeology

As digital cameras can take amazing close ups why not enhance your shots with this homemade diffuser set-up which costs only a couple of quid and a ½ hour to make.

The only thing you need is a half decen digital -camera with a good macro ability.

Now buy yourself a large funnel, (preferably white and semi-transparent) then after you have measured the width of your lens cut of the spout so the narrow

end of the funnel is a little larger than your lens (see photo on right).

Now cut the new funnel length  (from the wide end) to that of your camera’s

macro distance (it is critical you get this correct).

Now you have a stable camera keeper complete with built in macro spacer, a built in light diffuser and a stand to keep your camera square to the subject.

This now gives us the ability to take photographs using long exposures and so

small f-stops (especially useful when taking photographs of three-dimensional

artefacts).

Always try to use daylight, avoiding flash wherever possible.  If you have a badly worn coin try using an ordinary hand torch (diffused), keeping it low down to apply a low raking light across the coin (this is best done in darker conditions).

Try using backgrounds that are marginally different (blues/greens) from the

subject, which will not confuse the camera’s auto exposure system. (If you are

not brave enough for fully manual)

You can post process your image through a software program, to add a little

more contrast/brightness where necessary.

WARNING :

ensure that your lens does not foul the

funnel when you power up, You will

seriously damage your camera…

Photography in Archaeology

Most digital cameras can take amazing close-up shots and details, however

you must tell your camera what you are doing or it will end up with out of

focus shots.

To prepare your camera you must enable Macro mode (some cameras also

have a super macro for incredible detail).  This is normally achieved by

moving a dial or pressing a button with the icon of a flower (or a flower and

magnifying glass for super macro)

Now all you have to do is get close to the subject a photograph it.  Once again

although not essential I would recommend a tripod and use a short self-timer

to ensure no camera shake.

Take at least two photographs, one with and one without a

centimetre/millimeter and chroma scale.  (see appendix)    Keep the

background neutral, such as beige or light blue and ensure an even light,

whether this is achieved by using sunlight – or you can also use a daylight

lamp (a SAD lamp is perfect), which provides a bright but even light.

Photos can often end up looking washed out and the automatic mode will judge the colours of a scene incorrectly thus over exposing it.  What we will try to do here is force the camera to underexpose.

Virtually every camera has the ability to under or overexpose.  This is called exposure compensation and is indicated by a square icon with a + in the top corner and a – in the lower corner. +/-.  Pressing this button will normally bring up a scale running from -2 to +2 EV, and using either a dial or buttons you can choose the setting you want.

A setting of -1 will halve the exposure (making it darker) a setting of +1 will

double the exposure (making it brighter).   Experiment on the same subject to

see the effect.

This is one of the few techniques that can be replicated using photo software

on your PC.  Most washed out photographs can be ‘corrected’ by utilising

image editing software to  increase the  contrast and the  colour saturation

whilst reducing the brightness.

When to use flash and when not to can often confuse people.  You have seen

in the above  examples the way to force settings by turning off the flash, but

what about when you should use a flash?

If you have a lot of brightness in the background (a very sunny day or backlit

scene you can often end up with the camera influenced by the brightness in

the background and the foreground features are underexposed.

To ensure the feature is also visible you must force the flash to operate (which

does sound strange if you are taking a photograph on a sunny day)   To do

this (you may have to check your manual)  but alter the setting so that the

lightning icon is visible on the screen.  The flash will now go off regardless of

the conditions.

Now that the flash will take care of the foreground it is time to optimise the

background.    During the day it should be possible for the auto mode to

achieve the correct results, but you may still want to adjust the exposure

setting (see  Maintaining the Colour) and the same is true if you are

photographing in a dark room with light coming in from windows or doors.

This technique is useful to ensure that the lighting of your photograph is

consistent, and is known as Flash Fill.

Photography in Archaeology

Poor light can often ruin most photographs, and you may find yourself in

situations where poor light is your worst enemy.  Either inside a building, a

tomb chamber, or even in a deep (and of course shored) trench.  So how to

achieve the best results?    There are several professional ways to achieve it,

but for this guide here is the simple solution.

For best results, set your camera  to  Manual mode, which is normally done by rotating the dial to M on the camera.  Now you are able to alter and set the f-number and the shutter speed.

To let in the maximum amount of light you should select the smallest f-number available (f2.8 – f5.6)  and then choose a low shutter speed.  This setting will very much depend on the conditions and you may have to take several pictures to achieve the desired result.  (one of the beauties of Digital Photography)

Try 2.5 seconds to start and then step up or down the shutter speed to find the best – experiment and find what works, you can afford to take the photos and also you will soon know just the right setting for the situation without thinking.

It is impossible to hold a camera still for this length of time so a tripod is

essential, however you can make a stable platform out of many other items.

A set of level legs or a bucket with a scarf or gloves used to balance the

camera will do just as well.  Ensure you do not have the strap in the way and

also that none of the bucket or gloves get in the shot.

Unless you are completely in the dark, and can light the scene with a hand

held flash – turn OFF the flash.  Cycle through your flash options until you

have a symbol that shows a lightning flash with a line through it – this ensures

that the flash will not operate.

If you are having difficulty in auto focusing you will have to set the camera to

Manual Focus.  (you may have to read the instructions to see where to do

this, but often it is a switch between AF (Auto Focus) and MF (Manual Focus)

and then set it to infinity (  I ) or measure the distance and set it to the

relevant distance. (if your lens has manual settings marked on the barrel. A lot

of modern lenses don’t have them which is a pain)

To ensure you do not shake the camera when you press the shutter button,

put it on self-timer, with cameras often having a short and long timer – which

can also give you enough time to ‘escape’ from the shot as well.  Or use an

infra-red remote control unit, if available

Photography in Archaeology

How often do you take a photograph of a feature but end up with a shot that

makes it difficult to work out what the centre of attention of the photograph is

supposed to be?  This is where we can steal a trick from portrait photography.

The process is in essence the opposite of  the previous technique.  You want to have the specific subject of your photograph to be in clear focus while superfluous

background is out of focus to dramatically highlight the subject.

To adjust the depth of field you will once again set the camera dial to A or AV

(Canon) Now you can change the f-number, often by scrolling a dial or using

up/down buttons.  You should be able to see the  f-number change on the

screen.

Different cameras often have different available  f-numbers, the rule is the

same.  Small numbers  i.e. f2.8 create a short depth of field where only the

main subject is in focus.  So to ensure the feature (whether that is a cut or an

architectural element) is in sharp contrast to the background, choose an f-

number such as f2.8 – f5.6.  If you have a ‘portrait mode’ you could also try to

see if it gives the results you need.

You can also reduce the depth of field by zooming in on the feature (only ever

use the optical zoom – do not use digital zoom!)  and then standing

backwards (sounds daft…  zoom in and then step back.. but the results are

worth it) Or, move closer!

TIP :

The closer you go to the subject, the less Depth of Field you will

get and the further away, the more Depth of Field will be obtained.

NOTE :

Large f-numbers close the hole in the lens, letting in LESS light.  The camera must then compensate by taking a longer exposure, which can in turn increase the risk of camera shake. The higher the f-number the steadier you must hold the camera.  Tripods are cheap light and useful in many situations.

Photography in Archaeology

Often you are required to take general shots of either the site or trench or th

surrounding landscape.  It sounds easy and an automatic setting should tak

care of most situations.  But many shots have subjects that are both near an

far from the camera – the trick is to have it all in focus.  Too often either th

background or foreground are slightly blurred.  To sort this you will have t

increase your depth of field.

To adjust depth of field you will have to be in Aperture Priority mode.  This

set by turning the dial to A or in the case of Canon models AV.

Now you can change the f-number, often by scrolling a dial or using up/dow

buttons.  You should be able to see the f-number change on the screen.

Landscapes-and-General-Shots

A large f-number i.e f16 creates a large depth of field where subjects both

1-This shot has both the foreground subject and the background in sharp focus

near and far will be in focus.  Choose the

largest available which will be anything over f8

or even up to f16. (or  f32 if your camera has

such a setting)

You can also get a wide  depth of field by

zooming out to the widest angle your camera

can go and then add to that a high  f-number

will ensure a maximum range in focus.