dealing with common problems in photography Flashcards
1
Q
a blurred image
A
- focus blur is caused by the user incorrectly focusing the camera
- motion blur is caused by the photographers movements when the shot is take (increase your shutter speed or use a tripod)
2
Q
depth of field
A
- if the back ground is out of focus use a smaller aperture
- as the lens gets closer to the object depth of field is lessened, even when its shot at the smallest aperture and the background is still out of focus there is no real solution in this case
3
Q
problems with light or lack of it
A
the scene is too dark
- use a tripod so you can use a slow shutter speed
- change ISO settings to a high value
- use a flash gun
4
Q
on axis flash
A
a single axis flash generally gives very poor results
- it often gives hard shadows and the subject itself can look a little flat
5
Q
bounced flash
A
- a single flash can give acceptable results sometimes (the flash is bounced of a wall or something onto the subject)
- gives a natural light
6
Q
off camera flash
A
we can light our subject from any angle we want to
- copy
- oblique
- reflective
- transmitted
- co/axial
7
Q
flash outdoors
A
- a hand held flash gun can illuminate an area at night
- this can bring out colour and detail which may not be visible
8
Q
evidential photography
A
in a lab
- high quality images remain a big challenge
- good technique and lighting is critical
- difficult evidence- CDs, mirrored surfaces and metallic objects, curved objects and glass
9
Q
copy lighting
A
- normal two light sources set at 45 degree, good for flat objects and showing the shape of a 3d object although doesn’t bring out much surface detail
- a diffusion filter can minimise the shadows
10
Q
direct reflective lighting
A
normally one light source set at 10 degrees
- the technique helps to loose shadows we tend to lose appreciation of the overall shape and texture of an item
- not useable with reflective items
11
Q
oblique lighting
A
one or more light sources set at a fine angle
- brings out fine detail in positive or negative impressions
- creates shadow on the lee side of the impression which creates contrast and makes the mark visible
- might be good for objects like CDs
12
Q
transmitted light
A
light passing through our evidence
- the evidence is placed onto a glass or acrylic platform under which is a light source
- light passes through the glass and interacts with our evidence
- the technique works well for marks on glass or on tape or other similar transmissive materials
13
Q
ring lighting
A
the use of a special type of light source
- provides very even lighting
- often used for macro work
- effective at eliminating shadows
- provides even illumination
- the camera never gets in the way of the light
14
Q
exposure and metering
A
TTL metering has its problems
- measures the amount of light reflected from the subject but to do this it assumes that a typical object will reflect 18% of the light and attempts to set an exposure which reflects this fact
- where a scene contains lots of dark objects the camera will tend to overexpose the image
- where a scene contains lots of light objects the camera will tend to under expose the image
15
Q
a high key image
A
- an object with a lot of white will need to increase exposure and open the aperture to prevent under exposure opposite for a dark image
