Lenses & Exposure. Lenses. Exposure. Lens Options Depth of Field Lens Speed Telephotos Wide Angles. Light Control Aperture Shutter ISO Reciprocity

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1 Lenses & Exposure Lenses Lens Options Depth of Field Lens Speed Telephotos Wide Angles Exposure Light Control Aperture Shutter ISO Reciprocity

2 The Viewfinder Camera viewfinder Image Sensor shutter lens aperture

3 Lens Basics What is a lens Focal Length (for 35mm) Focus, Sharpness, Distortion Zoom Magnification 1x - 3x - 10x Lens Size Glass or Plastic Macro Focus Lenses

5 Aperture The aperture controls the amount of light passing through the lens. f/stops indicate the size of the aperture. Each setting is doubles the light volume admitted most lenses have 7 f/stop range

6 Depth of Field Out of focus Background In focus Center Out of focus Foreground

7 Lens Depth of Field camera subject Depth of field depends on lens focal length and aperture setting. Smaller apertures (f/16-22) provide greater DOF 1/3 2/3 Area in focus Wide angle Lenses have greater DOF Telephoto Lenses have less DOF DOF can be previewed on many SLR cameras.

8 Depth of Field Control Out of Focus Background pops Foreground object

10 Depth of Field -- Aperture Open Aperture Lens Type Closed Down Short DOF Telephoto Lens Medium DOF Medium DOF Normal Lens Long DOF Long DOF Wide Angle Lens Full Focus

12 Wide Angle Lenses They Stretch Space apparently distorting perspective It is called Wide-Angle Distortion For maximum effect Use short focal length lenses Get close to the subject Shoot at odd angles

13 Wide Angle Lenses They stretch space

14 Telephoto Lenses Flatten Space

15 Lens Speed Fast Lenses A Faster Lens Gathers more light They have larger wide open apertures They allow shooting with smaller ISO & faster shutter speeds They are expensive

Octagonal shaped spots from light falling directly on lens

16 Lens Hoods Critical Equipment They improve image contrast & sharpness They help prevent flare & sunspots Sunspots Octagonal shaped spots from light falling directly on lens Flare Washed out areas in the image from light bouncing into the lens.

17 Shutter Speed Shutter speeds double for each setting 1/60 1/120 1/250 1/400 1/800 Each doubling reduces the amount of light by one half. Bulb The shutter will remain open as long as the shutter is pressed. Time Press once to start, again to end.

18 Slow shutter speeds create motion blur. Motion blur Can create Impact

19 Slow Shutter Motion Blur Shutter Speed Fash Shutter Stop Action Subject Moderate Blur Extensive Blur Traffic Trails 30 sec 90 sec Waterfall 1/5 sec 1 sec Person Walking 1/30 1 /4 Person Running 1/60 1/15 Horse Trotting 1/30 1/8 40 mph 1/125 1/30 70 mph 1/250 1/60

20 ISO Speed Sensor speed = sensitivity to light measured As an index number called ISO speed. ISO speed Slow Less noise Fast More noise

21 2002, Mike Blevins

22 Exposure The total amount of light falling on the sensor The shutter Controls image motion The aperture -- Controls depth of field ISO Speed Controls image noise. Reciprocity A change in either of these can Offset a change in the other

23 Camera Exposure Controls 1. Automatic Exposure Control Camera computer sets everything 2. Scene Mode Controls Scene Selection sets Everything 3. Semi-automatic Exposure Control You set aperture or shutter 4. Manual Exposure Control You set everything

24 Scene Mode Easy Exposure Adjustments Sports Mode Landscape Mode Macro Mode Portrait Mode Night Mode Setting the scene tells the Camera what settings to use

25 END Section 1

TRIPODS Improve Image Sharpness Allow Dawn & Dusk Shots Architecture & Interiors Better Portraits Allows Small f/stop Landscapes Needed for Long

26 TRIPODS Improve Image Sharpness Allow Dawn & Dusk Shots Architecture & Interiors Better Portraits Allows Small f/stop Landscapes Needed for Long Telephotos THE TRIPOD RULE: The minimum shutter speed needed for a sharp negative Is the reciprocal of the lens Focal length. 250 mm = 1/250 sec 400 mm = 1/400 sec

27 Tripod Features Sturdy but strong, 5 -high, 2 -folded Light carbon composite is best Quick release head Pan-tilt or ball head Level (bubble) Under tripod extension Consider: Gitzo - carbon fiber, Slik - low cost Cullman (fold flat &monopod) Heads: Gitzo offset ball Slik small balls

Other Support Options: Monopod hiking stick Bean Bag transport unfilled (add beans/sand) Minimal table top tripod Shutter release cable or IR remote Gear

28 Other Support Options: Monopod hiking stick Bean Bag transport unfilled (add beans/sand) Minimal table top tripod Shutter release cable or IR remote Gear Bags: Backpack & belt mounted lens bags Lowepro backpacks are the most popular Hard case with foam inserts Photographer s vest Traditional carry case with straps

29 Lighting Issues Pop-Up Fill Flash, Use it frequently Separate electronic flash match to your system Rotating & swivel head Adjustable flash angle Diffusion add-on External cord to move light Lithium Batteries Reflector folding cloth cardboard/foil

30 Using Fill Flash Even a small camera-mounted fill flash will illuminate faces that would otherwise be dark. The exposure meter sets exposure for the total scene and the face is underexposed.

31 Filters To Control Light at the Lens The Basic Kit (for film cameras) Skylight, UV, or Haze (on all lenses) Circular polarizer (good quality 81A and 81B Warming Filter Neutral Density (1stop, 2stop, 3stop) Graduated (clear to ND: 2x, 4x, 8x stop) Color Graduated (Blue, Brown, etc.) Yellow, Orange, or Red for B&W For Digital Yes Yes * Yes Yes * * * Polarizers (use Circular on AF Cameras) Saturates colors, (blue sky pops clouds) Reduces or eliminates reflections (water, glass, etc) Can act as ND filter (1-2 f/stops) Not great for skin tones, overused. * There is a Photoshop work around

32 Cokin Graduated Gray Filters Cokin offers are variant of the normal filter system with several advantages. Filters are square which allows splitting the filters in the holder to get different effects. There are over 60 filters in their system.

33 Use of Graduated ND Filters Block Exposure by 2 stops Normal Exposure With Graduated ND Filter Without Filter

34 Beach without Graduated ND Filter Beach with Graduated ND Filter

35 Lenses & Exposure Lens Options Depth of Field Lens Speed Telephotos Wide Angles Light Control Aperture Shutter ISO Reciprocity

(and what the numbers mean)

Using Neutral Density Filters (and what the numbers mean) What are ND filters Neutral grey filters that effectively reduce the amount of light entering the lens. On solid ND filters the light-stopping