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Over the years
I've gather various tidbits of photography information that I've
found useful. The material is compiled from a large number of sources,
books, online reference, etc. If you have any suggestions (or corrections!)
please contact me.
 Sensor
Sizes
35mm frame: 24mm x 36mm
10D sensor: 15.1mm x 22.7mm
Crop Factors
35mm: 1.0
Canon 1Ds: 1.0
Canon 1D: 1.3
Nikon D100/D2H: 1.5
Canon 10D/300D: 1.6
Luminance
vs. Illuminance
Luminance = Amount of light reflected/emitted from a subject (what
a camera light meter measures)
Illuminance = Amount of light falling on a subject
Light
Value (Lv)
Lv = Log2(BK)
B = Subject Luminance
K = 86.2 is B is candela/sq foot.
K = 8.0 if B is candela/sq meter
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Light
Value Chart ( light reflecting off an ideal subject (18% grey
card) except for "emitted")
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|
17
|
Rarely
seen in nature |
5
|
Average
interior or auditorium |
|
16
|
Bright
sunlight off of sand or snow |
4
|
Christmas
or candle lights |
|
15
|
Bright
hazy sunlight |
3
|
Fireworks
(emitted) |
|
14
|
Weak hazy
sunlight |
2
|
Lightning
from a distance (emitted) |
|
13
|
Bright
cloudy day |
1
|
City skyline
at night (emitted) |
|
12
|
Overcast
day |
0
|
Dim ambient
light |
|
11
|
Shade on
a bright day or during sunrise/set |
-1
|
Really
dim ambient light |
|
10
|
Dusk or
dawn |
-2
|
Full moon
off of sand or snow |
|
9
|
Late dusk
or early dawn |
-3
|
Full moon |
|
8
|
Times square
at night |
-4
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Half moon |
|
7
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Brightly
lit street |
-5
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Crescent
moon |
|
6
|
Bright
interior |
-6
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Starlight |
f-number
Diameter of lens aperature with respect to focal length
Example: f/4 means aperature diameter is 1/4 the focal length
f-stop
Each stop = halving of light
Powers of square root of 2 - amount of light (area) is function
of diameter squared
Examples: f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22
"Odd" values like f/3.5 are common
Shutter Speed
Length of time shutter is open
Examples: 1/30, 1/60, 1/250, etc.
Exposure
Value (Ev)
Ev = log2(Aperature^2/Shutter Speed)
Ev0 = f/1.0 at 1 second
An Ev increase of 1 = halfing of light admitted
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Exposure
Value Chart - Ev and Corresponding Shutter/Aperature Settings
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Aperature
|
|
Shutter
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f/1
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f/1.4
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f/2
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f/2.8
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f/4
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f/5.6
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f/8
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f/11
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f/16
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f/22
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f/32
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1
sec
|
0
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
1/2
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
|
1/4
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2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
|
1/8
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
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1/15
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4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
|
1/30
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5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
|
1/60
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
|
1/125
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
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1/250
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8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
|
1/500
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9
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
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1/1000
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
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1/2000
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
21
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1/4000
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
21
|
22
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Film Speed
Defined by International Standard Organization (ISO) 5800:1987
Specific to film, but adopted by digital cameras
Examples: ISO 100, ISO 200, ISO 400, etc.
Double ISO doubles sensitivity to light thus requiring half as much
light for proper exposure
Higher ISO = more grain (film) or more noise (digital)
Correct Exposure:
E = L + S
E = Exposure Value (Ev)
L = Light Value (Lv)
S = Speed Value (Sv) = Log2(ISO Speed / 100)
For ISO 100: Ev = Lv, yields proper exposure
ISO 200: Ev = Lv + 1, ISO 400: Ev = Lv + 2, etc.
Exposure
Latitude
The range of brightness a film/sensor can record
Human Eye: 11-30 Lv
Print Film: 5-7 Lv
Slide Film: 3-5 Lv
Digital (in-camera processed): 3-5 Lv
Digital (raw): 4-6 Lv
Exposure outside of this range results in loss of shadow detail
or blown highlights. If the subject's luminance range falls within
the exposure latitude, the entire subject can be properly exposed.
Light Temperature
|
Temperature
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Scene |
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10,000K
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High
altitude, clear blue day |
|
9,000K
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Rainy
Daylight |
|
7,000K
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Overcast
Daylight |
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5,600K
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Daylight
Standard |
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5,000K
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Noon
Daylight, Direct Sun |
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4,500K
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Electronic
Flash (4500K-6000K) |
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4,000K
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Flurorescent
(4000K-5000K) |
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3,500K
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Sunrise
/ Sunset |
|
3,200K
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Indoor
"White" Light Standard, Quartz (Tungsten-Halogen) |
|
2,500K
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Household
Lightbulbs |
|
2,000K
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Early
Sunrise |
|
1,200K
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Candlelight |
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