Dealing with common problems-Richard

Question 1

blurred image

Answer 1

focus blur is caused by the user incorrectly focussing the camera

motion blur is caused by the photographer’s movements when the shot is taken

Question 2

lack of light

Answer 2

use a tripod so can have a slow shutter speed
change ISO settings to a high value
use flash gun

Question 3

on axis flash

Answer 3

a single on-axis flash gives poor results

gives hard shadows and the subject can look flat and 2 dimensional

results can be improved by using a diffuser which softens the light

Question 4

bounced flash

Answer 4

by bouncing our light off a surface such as the ceiling or indeed a wall we produce indirect diffuse soft light

gives more natural light

done by pointing flash directly upwards or slightly rearwards and can be further enhanced with a reflector card

Question 5

problem with bounced flash?

Answer 5

painted walls will influence colour of flash

Question 6

off camera flash

Answer 6

many can be controlled remotely

Question 7

name 5 ways we can light our subject using a flash?

Answer 7

copy
oblique
reflective
transmitted/backlit
co/axial

Question 8

painting with light

Answer 8

illuminates large areas outdoors

Question 9

copy lighting

Answer 9

normally two light sources set at 45 degrees

good for flat objects and many 3D objects

doesn’t bring out as much surface detail

problematic shadows possible with smaller light sources

shadows can be minimised by using simple diffusion filter or even some paper or white materials the light can be diffused enough to prevent shadows from being too distracting

if only a single light is available, position a reflector in place of the second light source

Question 10

direct reflective lighting

Answer 10

normally one light source set at 10 degrees

camera is offset so that the overall angle between camera and light source is about 20 degrees whilst being parallel to the object

helps remove shadows however lose an appreciation of the overall shape and texture of an item

tends to produce fairly high contract images and is not useable with reflective items

Question 11

oblique lighting

Answer 11

one or more light sources set at a fine angle

brings out fine detail

creates shadows on lee side of impression thus increasing contrast and making out mark visible

Question 12

transmitted lighting

Answer 12

light passing through evidence

evidence placed onto glass or acrylic platform under which is a light source

light passes through glass and interacts with evidence

can move light source producing both bright field and dark field effects

Question 13

ring lighting

Answer 13

camer lens passed through the hole and the object is bathed in light at an angle

used for macro work

effective at eliminating shadow and tend to provide very even illumination although may not always bring out fine surface detail

camera will never get in way

Question 14

TTL metering

Answer 14

measures the amount of light reflected from the subject but to do this it must assume:
-a typical object will reflect around 18% of the light that hits it and attempts to set an exposure which reflects this fast

Question 15

what is high dynamic range

Answer 15

the ratio between the most bright and the least bright areas of a scene

Question 16

solutions to high dynamic range problems

Answer 16

1) average exposure
- set aperture, set the camera to spot metering, note down correct shutter speed for each area and pick shutter speed between the two
2) fill in flash
- set aperture, set camera to spot metering, attach flashgun

Question 17

white balance

Answer 17

all Nikon camera can adjust white balance automatically but sometimes they don’t get things right

resulting images can have a distinct colour cast due to the colour of the incident lighting

can be corrected by adjusting the white balance of the camera or in post-processing software

Question 18

colour critical applications

Answer 18

all evidence scales include black white and grey sections