Short Guide to Digital Photography in Archaeology

:: Short Guide to Digital Photography in Archaeology ::
© BAJR

:: June 2006

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BAJR Guide – Short Guide to Digital Photography in Archaeology
Introduction

Many of us now use Digital Cameras in place of 35mm and are expected to
be able to use them, relying on the automatic setting to get the photograph we
need. However certain conditions require more than just point and click. This
short guide is to give a rough guide to 6 conditions where manual settings are
more appropriate and wil help you understand more about how to take
photographs in general.

The 6 settings we will discuss are:

1.
Landscape and “general shots”
2.
Keeping the feature in Focus
3.
In the dark
4. Using
Flash
5.
Maintain the colour
6. Close-up
finds
shots

This is not a comprehensive guide to site photography, but is intended to
allow anyone to take decent photographs with the minimum of knowledge. It
should also been seen as a starter for those who want to take it further, as like
anything, a grasp of the theory allows more comprehension of the ‘why’ and
‘how’ that is never available in the age of automatic settings and software
fixes.


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BAJR Guide – Short Guide to Digital Photography in Archaeology
1 - Landscapes and General Shots.

Often you are required to take general shots of either the site or trench or the
surrounding landscape. It sounds easy and an automatic setting should take
care of most situations. But many shots have subjects that are both near and
far from the camera – the trick is to have it al in focus. Too often either the
background or foreground are slightly blurred. To sort this you wil have to
increase your depth of field.
To adjust depth of field you wil have to be in Aperture Priority mode. This is
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/down
buttons. You should be able to see the f-number change on the screen.

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


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BAJR Guide – Short Guide to Digital Photography in Archaeology
near and far wil be in focus. Choose the NOTE :
largest available which will be anything over f8 Large f-numbers close the
or even up to f16. (or f32 if your camera has hole in the lens, letting in
such a setting)
LESS light. The camera

must then compensate by
You can also get a wide depth of field by taking a longer exposure,
zooming out to the widest angle your camera which can in turn increase
can go and then add to that a high f-number
the risk of camera shake.
wil ensure a maximum range in focus.

The higher the f-number the
steadier you must hold the
camera. Tripods are cheap
light and useful in many
situations.
2 - Keeping the feature in focus.

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
TIP :
the previous technique. You want to have
The closer you go to the subject, the specific subject of your photograph to
the less Depth of Field you wil be in clear focus while superfluous
get and the further away, the background is out of focus to dramatically
more Depth of Field will be highlight the subject.
obtained.

To adjust the depth of field you wil 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!


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BAJR Guide – Short Guide to Digital Photography in Archaeology
2 - The merkat-cross head is in focus and the background is slightly out of focus, which
highlights the subject.

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BAJR Guide – Short Guide to Digital Photography in Archaeology
In the dark.

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
TIP :
to Manual
mode, which is
Digital cameras often autofocus on normally done by rotating the dial
whatever it is pointed at, so if the feature to M on the camera. Now you are
you want to highlight is off centre there is able to alter and set the f-number
a way to ensure that the focus remains and the shutter speed.
on it. Centre on the feature and half
depress the shutter button, and you wil To let in the maximum amount of
hear the camera focus. Now while light you should select the
remaining half depressed, move and smallest f-number available (f2.8
recompose the shot, before finally fully – f5.6) and then choose a low
depressing the button and taking the shutter speed. This setting wil
photograph.
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)

3 - This highlights the two problems of low lighting and light glare, with automatic
settings unable to cope with the situation.


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BAJR Guide – Short Guide to Digital Photography in Archaeology
.Try 2.5 seconds to start and then TIP :
step up or down the shutter If your camera has no fully manual
speed to find the best –
mode, you can get a similar result by just
experiment and find what works, switching the flash off in Automatic
you can afford to take the photos mode. This wil force the camera to a
and also you wil soon know just longer exposure than the 1/60th
of a
the right setting for the situation second that is normal for flash shots.
without thinking.
Remember you are looking for exposure

over 1 second.
Cameras indicate seconds by the ” symbol, so 4” is four seconds (you will see
the same usage in survey - 340° 14’ 45” is 340 degrees 14 minutes and 45 seconds) .
It is impossible to hold a camera stil 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 wil not operate.

If you are having difficulty in auto focusing you wil 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


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BAJR Guide – Short Guide to Digital Photography in Archaeology
Using flash.

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?

4 – A flash exposure of 1/60th il uminates the wall, but does not stop overexposure
from the daylight.

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 wil now go off regardless of
the conditions.

TIP :
A normal flash has a range of only a few
metres, but will still add much needed
light to a foreground subject, even on a
sunny day.

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BAJR Guide – Short Guide to Digital Photography in Archaeology
Now that the flash wil 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 stil 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 Fil .

5 – A near perfect flash fil , both the wall and exterior are balanced for exposure. The
camera was set on a tripod on a 1/250th second exposure (for the background) and a
forced flash fil on the foreground) Note also the reuse of the technique seen in
section 2 – where the foreground (the subject) is in focus, while the background is
slightly out of focus! - Sorry about the car though… sometimes you have to take your time and
wait for the right moment.. Even if it takes hours!

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BAJR Guide – Short Guide to Digital Photography in Archaeology
Maintain the colour

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

TIP :
Virtually every camera has the ability to
Whenever you change your settings under or overexpose. This is called
manually, always remember to return
them to default values. Turn flash back
exposure compensation and is indicated
on, reset manual focus to automatic by a square icon with a + in the top corner
etc.
and a – in the lower corner. +/-. Pressing
this button wil normally bring up a scale
If you forget to set the EV back to zero,
running from -2 to +2 EV, and using either
all your photos will be either too dark or
washed out.
a dial or buttons you can choose the
setting you want.

A setting of -1 wil halve the exposure (making it darker) a setting of +1 wil
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.
6 – Washed out, sun blurred, foreground too dark – yes….that’s the automatic mode.

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