iso and white balance. iso refers to the light sensitivity of the sensor iso – international...

ISO and White Balance

ISORefers to the light sensitivity of the sensor

ISO – International Standard Organisation

HIGH ISO value means the sensor will be MORE sensitive to light, meaning it will take LESS LIGHT to

get the right exposure

Similar to Film Speeds in 35mm format

ISO

Typically ranges from 100-1600

Newer Digital cameras have a higher range

(up to 64000)

Using High ISO values causes the sensor to produce much more heat, which creates digital “noise” in

images.

ISO

Noise is similar to film grain and causes loss of fine detail in images

It is more visible in dark parts of an image and is generally more noticeable when displayed on screen

than in print

ISO

ISO

ISO

Some cameras claim to have “Digital Image Stabilization”

This just means that the camera will automatically increase the ISO in order to allow a faster shutter

speed

Faster Shutter Speed will reduce the likelihood of camera shake, but high ISO will most likely result in a

grainy image.

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Exposure Compensation

Way to control your exposure

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Cameras Meter Selects an aperture/shutter speed

combination that it believes will give a properly exposed picture.

sometimes determines the wrong exposure value needed to correctly expose the image. *

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Exposure Compensation Slightly over-exposing the image or

slightly under-exposing the image.

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Why do we use it.

To ensure a properly exposed photo.

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Universal Symbol

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Exposure Compensation

Exposure Value + Adds more light to pictures

Makes Lighter - Subtracts light from pictures

Makes darker +/- 2 EV *

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EV COMPARISION

EV = -2 EV = -1  EV = 0 EV = +1 EV = +1.3

  EV = +1.6  

 EV = +2

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Normal Exposure

Most average scenes reflect 18% of the light that falls on to them.

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Bright Scenes Reflect more than

18% of the light. Beach Scenes Bright sand Snow covered

landscapes You need to

subtract exposure (make darker)

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Dark Scenes Reflect less than 18% of

the light falling on them. Deep shadows Dark Foliage Black Cloth

You need to increase your exposure (make lighter)

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Others

Subject against a very light background. Main subject will be dark

Subject against very dark background. Main subject will be to light.

Scenes with High Contrast

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Summary To lighten a

picture, you increase the exposure (+).

To darken an image, you decrease the exposure (-)

White Balance

• Critical to “look” of the photograph

• Instructs camera computer how to interpret colors it sees

• Set based on temperature (degrees Kelvin) of the primary light source

• Incorrect White Balance can cause colors that are too warm (red) or too cool (blue)

White balanceHere is a list of some common light Here is a list of some common light sources and their colour temperature in sources and their colour temperature in Kelvin.Kelvin.

Temperature —–> Typical SourcesTemperature —–> Typical Sources1000K —–> Candles; oil lamps1000K —–> Candles; oil lamps2000K —–> Very early sunrise; low 2000K —–> Very early sunrise; low effect tungsten lampseffect tungsten lamps2500K —–> Household light bulbs2500K —–> Household light bulbs3000K —–> Studio lights, photo floods3000K —–> Studio lights, photo floods4000K —–> Clear flashbulbs4000K —–> Clear flashbulbs5000K —–> Typical daylight; electronic 5000K —–> Typical daylight; electronic flashflash5500K —–> The sun at noon5500K —–> The sun at noon6000K —–> Bright sunshine with clear 6000K —–> Bright sunshine with clear skysky7000K —–> Slightly overcast sky7000K —–> Slightly overcast sky8000K —–> Hazy sky8000K —–> Hazy sky9000K —–> Open shade on clear day9000K —–> Open shade on clear day10,000K —–> Heavily overcast sky10,000K —–> Heavily overcast sky11,000K —–> Sunless blue skies 11,000K —–> Sunless blue skies

White Balance Goal

• Achieve a neutral colorcast in your photo

• Get whites to look white

• Get colors to look like what you saw when you took the photo

White Balance Importance

• JPEG vs. RAW

• When true color rendition is critical– Weddings– Portraits– Product Photos

Setting White Balance

• Before shooting– Auto– Camera Menu choices (e.g., direct sunlight,

cloudy, shade, flash, fluorescent (7 choices), incandescent, set color temp)

– Manual Preset• Gray card photo• Expodisc• Neutral color photo

Expodisc

White Balance

Adjusting White Balance

• After shooting– JPEG – not directly adjustable– RAW – fully adjustable in most processing

software• Menu choices• Gray card photo• White point/Gray point tools

Examples

Hi Temp Merc Vapor (7200K) Sodium Vapor (2700K)

Examples

AUTO WB Cool White Fluorescent (4200K)

Examples

Incandescent (3000K)Set Gray Point on Cheerleader’s

Arm

Examples

AUTO WBSet Gray Point on Cheerleader’s

Arm