Fundamentals of Photography presented by Keith Bauer kcbauer@juno.com http://keithbauer.smugmug.com
Homework Assignment Composition Class will be February 7, 2012 Please provide 2 images by next Tuesday, January 31st Long edge 1024 pixels 72 dpi - Save at a size <= 300K srgb color space If you are sure you know how to prepare the image email as attachment to me at kcbauer@juno.com If not: Bring in a CD, or USB drive next week
Exposure Triangle ISO Shutter Speed Aperture ISO
Shutter Speed
Simply controls the duration of the shutter Expressed on the camera as values like 1000, or 125, or 60 Which really mean 1/1000, 1/125, 1/60 Most modern SLR s have a shutter speed range from 30 to 1/4000 or 1/8000 Shutter speed either doubles or halves depending on which way you choose to move Controls motion
Aperture
A = * R 2 R= 1 So the Area is
A = * R 2 R=? What Radius will be required to create an area of 2 R = 2
1 1 * 1.4 = 1.4 1.4 * 1.4 = 2 2 * 1.4 = 2.8 2.8 * 1.4 = 4 4 * 1.4 = 5.6 5.6 * 1.4 = 8 8 * 1.4 = 11 11 * 1.4 = 16 16 * 1.4 = 22
F-Stops or Apertures are a ratio of Focal Length / Size of hole created by the aperture Example: 50mm lens / 25mm hole = f / 2 50mm lens / 3 mm hole = f / 16 Hence: Small holes are represented as large f / stop numbers Large holes are represented as small f / stop numbers
Precise Focus is only possible at one distance - A point object will produce a point image Note the variables that affect Depth: Focal Length Subject Distance Aperture Circle of Confusion At any other distance the point will be defocused and produce a blur the shape of the aperture
Remember this little jingle in your head Big f / Stop Numbers = Big Depth Little f / Stop Numbers = Little Depth
DOF Preview If you have a DOF preview button on your camera This is a great way to see what will be acceptably sharp Remember - you are looking through your lens with it wide open DOF Preview stops down the lens to the selected aperture Let your eyes adjust - f/16 is pretty dark in there!!
ISO
Full Frame Sensor 1.6x Cropped Sensor
ISO - International Organization for Standardarization Doubling the numerical value doubles the sensitivity of the sensor Each camera has a base ISO Typically it is either ISO 100, or ISO 200 The range of ISO that a camera supports varies based on make/ model ISO 100 - ISO 6400 or 12800 (even 25600)
So why not just crank up the ISO Noise or Grain
f/2.8 f/4 f/5.6 f/8 f/11 f/16 f/22 f/32 1/30 1/60 1/125 1/250 1/500 1/1000 1/2000 1/4000 A X B Y A X B Y A X B Y A X B Y X B Y C B Y C Z B Y C Z Y C Z
There s more than Full Stops 1/2 Stop Increments f/4, f/4.8, f/5.6, f/6.7, f/8 f/9.5, f/11, f/13, f/16, f/19, f/22, etc. 1/30, 1/45, 1/60, 1/90, 1/125, 1/180, 1/250, 1/350, 1/500, etc 1/3 Stop Increments f/4, f/4.5, f/5, f/5.6, f/6.3, f/7.1, f/8, f/9, f/10, f/11, f/13, f/14, f/16 1/30, 1/40, 1/50, 1/60, 1/80, 1/100, 1/125, 1/160, 1/200, 1/250, 1/320, 1/400, 1/500, 1/640, 1/800, 1/1000, etc.
Exposure Triangle ISO Shutter Speed Aperture ISO
Light Meters
Two Types of Light Meters Incident Light Meters These measure the amount of light falling on the subject Very precise if you can place the meter in the same light as the subject
Two Types of Light Meters Reflected Light Meters The meter that is in your camera Measure the amount of light reflected from the subject
What s the Standard Reflected Light meters assume 18% of the light is reflected Hence they assume 82% of the light is absorbed or not reflected back to the meter That works fine in many situations North Blue Sky, Green Grass, Neutral gray card But... What happens if the subject doesn t reflect 18% of the light
Exposure Compensation Your mechanism to override the suggested metering value You can alter the suggestion in 1/2 or 1/3 stop increments Positive Exposure compensation adds light to the exposure Negative Exposure compensation subtracts light from the exposure
When to use it Extremes Predominately White or Black subjects Wedding dresses, snow Black Tuxedos,
Other Situations Many other situations You must be aware of what is in the viewfinder and what the meter is allowed to see
Metering Patterns Evaluative or Pattern or Matrix Partial Spot Center Weighted
Exposure Bracketing Taking Multiple exposures at varied exposure settings Example: 3 stop sequence at -2, 0, +2 Darker than suggested, At Suggested, Brighter than suggested Can be done automatically in your camera Most cameras will do a 3 stop bracket. Some will do 5, 7, or 9 shot brackets with increments of 1/3, 1/2, full or multiple full stops
Exposure Modes Program Mode (P) Camera controls Shutter Speed, Aperture and in some cases the ISO used to capture the image
Exposure Modes Aperture Priority (A or Av) YOU decide what aperture you want to use, and the camera selects the shutter speed that creates the correct exposure based on the ISO setting that you ve selected
Exposure Modes Shutter Priority (S or Tv) YOU decide what shutter speed you want to use, and the camera selects the aperture that creates the correct exposure based on the ISO setting that you ve selected
Exposure Modes Manual (M) YOU decide what shutter speed AND aperture you want to use to create the correct exposure based on the ISO setting that you ve selected
Flash
Flash Sync Speed The Sync speed is the fastest shutter speed on your camera when both the front and rear curtains of the shutter are completely open This typically somewhere around 1/200 or 1/250 At any shutter speed faster than the sync speed, the shutter is really a moving slit to expose the sensor
Standard Flash Sync Time 1st Curtain Exposed Sensor Single Flash Burst 2nd Curtain
High Speed Flash Sync Time Exposed Sensor 1st Curtain Strobes Flash Bursts 2nd Curtain
Front & Rear Curtain Sync Front Curtain Sync fires the flash as soon as the front curtain is completely open Rear Curtain Sync fires the flash just before the rear curtain begins to close
2 Components of a Flash Image Flash Ambient Aperture affects the amount of Flash that contributes to the exposure Shutter affects the amount of Ambient that contributes to the exposure
Fill Flash vs Flash as Main Light Fill Flash Intended too fill shadows with some light Not overpowering Should not be noticeable Usually requires negative Flash Compensation Can help control dynamic range of an image Flash As Main Light Flash becomes the only light source - i.e. Ambient contributes zero
Balancing Ambient and Flash 100% All Ambient - No flash 0% Flash Contribution to Exposure Balanced Fill Flash Ambient Contribution to Exposure 0% All Flash - No Ambient (Flash as Main Light) 100%
Lenses
What are all those Numbers Canon Zoom Telephoto EF 70-200mm f/2.8l IS USM Autofocus Lens Canon Zoom Telephoto EF 70-200mm f/4l IS USM Autofocus Lens Canon Zoom Telephoto EF 70-300mm f/4-5.6 IS Image Stabilizer USM Autofocus Lens $2100 $1281 $549.00 Filter 77mm Filter 67mm Filter 58mm
Lens Perspective The perspective of the image changes based on the focal length of the lens camera to subject distance 300mm The longer the lens, the more compression occurs in the image Wide angle lenses seem to push subjects away 150mm 50mm 20mm
Filters
Circular Polarizer
UV Haze
Neutral Density
Graduated Neutral Density
Tripods and Heads
Tripods My advice Buy the best tripod you can afford
Arca Swiss Style Mount Ball Heads
Gimbal Mounts Wimberly 4th Generation Design Mongoose Kirk King Cobra...