Sikes Digital photography 1 week 2 exposure (57 slides)Presentation Transcript
DigitalPhotography I Aperture ISO Shutter Speed
The Exposure TriangleDigital Photography I
ExposureThis is by far the most technical lesson of this session.However it is essential to begin to get a grasp of theexposure triangle concept.You must refer to your personal camera manual in orderto completely understand how to use the creative modes.Refer to the handout and take notes when necessary.
ExposureExposure is the total amount of light that you allow into the camera
Exposure Triangle ISO Changing any of the three elements will effect the exposure Shutter Aperture SpeedAperture and shutter speed are inversely proportional to each other.
Camera Configuration Digital Sensor Shutter Aperture Lens
ExposureToo much light results in an over-exposed image where there are areas of bright white or ’blow-outs’. These areas contain no detail or color. 8
ExposureToo little light results in anunder-exposed image wherethere are areas of low detail. 9
ExposureGreat differences in light within a photographconfuses the camera. The camera exposes to the bright light , thereforethe darker portions of the photograph are blacked out. Vatican, Rome
Shutter Speed Posing for 19th century photographs Usually took as much a 5 minutes of Sitting perfectly still. Luckily, today we can control Shutter speeds. Opelika, AL
Shutter Speed• Shutter Speed—the amount of time the shutter is open— which determines how much light is captured in the recording process – Measured in seconds: super fast 1/2000 second to 30 seconds – The slower the speed, the longer light can enter the camera. Appropriate for shooting pictures in darker situations; also great for freezing action and movement Shutter speeds and aperture (f-stops) are inversely proportional. 13
Shutter SpeedShutter speed is measure in fractions of a second.A shutter speed greater than 1/60th second requires the use of a stabilizing device like a tripod. Without stabilization, the photograph will not be crisp and clear. 15
Low Light requires longer shutter speeds and a tripodFull 1 second shutter speed Langdale Mill
Low Lightrequires longer shutter speeds and a tripod
Shutter Speed Must use A tripod Best for Sports shots
ISO• ISO is the measurement of how sensitive the image sensor in the camera is to light. – Measured in numbers 100, 200, 400, 800, etc. – Use a lower number when smooth crisp images are need and you have plenty of light. – Higher numbers are used when light is limited, you do not want to use a flash, or the subject is moving; may result in grainy images 20
The Exposure Triangle ISO – International Organization of StandardizationISO—the measurement of the sensitivity of the camera image sensor to light. Measured in numbers 100, 200, 400, 800, etc. – Lower numbers used when smooth crisp images are desired and you have plenty of light. – Higher numbers are used when light is limited, you do not want to use a flash, or the subject is moving; may result in grainy images 21
ISOISO is the measurement of the sensitivity of the camera image sensor to light. An ISO of around 200 is average. 22
ISOAn ISO of around 200 is average.Lower numbers are used when smooth crisp images are needed and you have plenty of light. Below 200 23
ISOAn ISO of around 200 is average.Lower numbers are used when smooth crisp images are needed and you have plenty of light. Below 200 24
ISOHigher numbers are used in • limited light conditions, • Flash is not desirable • subject is moving • May result in grainy images 400 and above 25
Choosing ISO Setting100 to 200 -------Outside Bright Sun400----Shade or overcast conditions400----Bright light indoors800-1400----Stormy day800-1400 – Low light indoors
Higher ISO 400 ISO 800 ISOLight is limited and flash was not desirable in either shot.
ISO Too little light can leave parts of your image too dark to make out details.If the ISO had been higher this photograph would have been brighter. Trevi Fountain, Rome 28 ISO 200
High ISOThis photo taken withISO 800. Notice the grainyappearance. This is callednoise. Rome by night 29
ISO 160 Notice the camera exposes to the light not the bride.More advanced cameras have amechanism that will allow you toexpose to individual areas with inthe shot. 30
Aperture f-stopsAperture is the camera feature that regulates the amount of light that passes through the lens by controlling the size of the openingin the lens. It is measured in f/stops.
Aperture f-stopsAperture is the camera feature that regulates the amount of light that passes through the lens by controlling the size of the openingin the lens. Described as the f/stop the smaller the number Stopping down the wider the lens will open
Aperture f-stops The common range for f-stops goes from f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22 Narrow depth of fieldf/8 is a good average aperture whereMost everything will be in focus. Infinite depth of field
F/stops and depth of fieldLower f stops need less light to expose Higher f stops need more light to expose Depth of Field Depth of Field decreases increases f/2 f/8 F /22
Aperture f-stopsFull f-stops go fromf/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32Each full stop value increase, decreases the light entering the cameraby half. Fast lens Slow lens Shorter shutter speed Longer shutter speed Large depth of field Narrow depth of field
Greater Depth of field Longer Shutter Speeds Aperture More exposed Narrower Depth of Field37
Shutter Aperture Relationship The smaller the aperture, the longer the shutter speed The larger the aperture, the shorter the shutter speed.
Sunny Sixteen RuleThe "rule of sunny-16" is simply a handy trick to rememberaway to set proper exposure when the sun is high in the skyAnd casts strong shadow on a bright day.The camera aperture is set to f/16(hence the -16 in sunny-16). dark shadows. The sunny sixteen rule was NOT used in this photoghraph.
Sunny Sixteen RuleAperture Aperture Stops stops Conditions conditionsf/22 -1 stop snow or beach bright daylightf/16 sunny-16 dark shadows weak or hazy sunf/11 +1 stop sun low in skyf/8 +2 stops cloudy bright darker cloudsf/5.6 +3 stops subject in shadowf/4 +4 stops sunset
Issues with each exposure point ISO Noise Changing any of the three elements will effect the exposure Shutter Aperture Speed Depth of Field Motion BlurAperture and shutter speed are inversely proportional to each other.
Manual Settings Dial
Creative Camera Modes Point and Shoot Modes Creative modes
Program Mode PShutterspeed (exposure) and Aperture are set in unison automatically.When you change the shutter speed, the aperture changes automaticallyWhen you change the aperture, the shutter speed changes automatically
Aperture Priority Mode Av Use Av when : Want everything In focus (use high f/stop) ORWant the background to be out of Focus (use low f/stop) In AV mode, the aperture remains constant. By turning the main dial on your camera, you can adjust the shutter speed. The aperture remains the same.
Shutter Priority Mode Tv Action shot modeIn Tv mode, the shutter speedremains constant.By turning the main dial on yourcamera, you can adjust theaperture. The shutter speed remains thesame.
Manual exposure modeIn M mode, the aperture and the shutterspeed can be altered.By turning the main dial on your camera, youcan adjust the shutter speed. The aperture remains the same.Read your camera manual to determin how to set boththe Av and the Tv In the Canon Rebel Set the Tv by turning the dial Set the Av by holding down the Av button and turning the dial.
Manual exposure modeIn the Canon RebelSet the Tv by turning the dialSet the Av by holding down the Av button while turning the dial.
Manual exposure modeIn the Canon RebelSet the Tv by turning the dialSet the Av by holding down the Av button while turning the dial. The standard exposure level is achieved when the slide bar is located in the center. This meter may be viewed on the LCD screen or through the view finder
AE Lock Consult your camera manual for AE lock stepsExposed to the light (normal ) Exposed to a chosen darker subject in the photo ( AE lock)
Automatic Depth of FieldCanons auto depth of field (A-DEP) feature works by (1) finding the nearest and furthest of all theautofocus points, (2) setting the cameras focusing distance to optimally position the depth of field between these nearest and furthest points, and(3) setting the aperture so that the edges of thedepth of field extend far enough to containthese nearest and furthest points.