"I eagerly await new concepts and processes. I believe that the electronic image will be the next major advance. Such systems will have their own inherent and inescapable structural characteristics, and the artist and functional practitioner will again strive to comprehend and control them."

- Ansel Adams, "The Negative" 1981

Shooting DigitalShooting DigitalTheory & Technique

Image Essentials

Color Theory

Camera Settings

File Formats

ISO

White Balance

Color Space

Digital Exposure

Histogram

Panoramas

Composites

Traveling

Shooting Problems

WarningThe following program contains:

Graphic Images

Abstract Concepts

Mild Mathematics

Viewer Discretion is Advised

Image Essentials

The Digital Image

The PixelA swatch of a single color

Raster Grid or Bitmapped Image

How is a digital image different from a film image?

– Mosaic of tiny squares called pixels

– Small size creates Illusion of continuous tone

Image Size• 3 ways to describe the size of an image• 1) Pixel Dimensions

– Number of pixels along horizontal & vertical axes– Determined by settings in camera

• 2) Megapixels– Total number of pixels in image– The greater the number of pixels in your image, the

larger size you can print and maintain fine detail

File Size• To your computer, each pixel is really only a To your computer, each pixel is really only a

series of numbersseries of numbers• 3) File Size

– Measurement of all those zeros & ones that make up your image

– Measured in units called bytes and megabytes– Indicates how much space your image takes up on

a hard drive or in your computer’s memory

= 238, 128, 217 =0011001000110011001110000010000000110001001100100011100000100000001100100011000100110111

One

pixel

What you What you seesee

What What Photoshop Photoshop

seessees

What your What your computer seescomputer sees

Resolution

• No matter how large or small you display your image it will have the same pixel dimensions; the same total number of pixels– The pixels just get larger or smaller– The greater the number of ppi; the better the illusion of

continuous tone & the better the quality of the image

• In your camera a digital image has no inherent size – it’s only numbers– Gains size when you display it (print, monitor, or web)

• Resolution is the density of pixels in a displayed image– Similar to population density (how many in a given space)– Measured in pixels per inch

Different size chessboards; same number of squares

Pixel depth (bit depth) One more factor that affects image quality:

How many possible values can each pixel have?

22

44256256

Pixel: Monochrome Image

Each pixel can be sorted into 256 levels of brightness from 0 for black to 255 for white,

with 254 gray levels in between

Color TheoryColor Theory

Just as a cake can be described by Just as a cake can be described by the relativethe relative amounts of sugar, flour, amounts of sugar, flour, eggs, it contains, so a pixel’s color eggs, it contains, so a pixel’s color is described by the proportions of is described by the proportions of

its ingredients: the 3 primary colorsits ingredients: the 3 primary colors

Part 1

Primary Colors

Additive Primaries Red, Green, Blue

Cameras, Monitors, Projected Light

Subtractive Primaries Cyan, Magenta, Yellow

“Process Colors”Inks, Printers

Traditional Primaries Red, Yellow, Blue

Paints

All colors in a digital photo result from a mixture of the 3 primaries: Red, Green & Blue

Different sets of primary colors for different media

Pixel as Recipe– The amount of each primary in a color can be expressed on a scale

of 0 to 255

– Any colored pixel is a recipe of the numerical amounts of red, green and blue that make it up

–Each pixel can have 256 possible values per primary–256 x 256 x 256 = over 16 million possible colors !!!

Pixel as Recipe

Each pixel has a unique numerical recipe that determines its colorEach pixel has a unique numerical recipe that determines its color

3 Channels

– an isolated look at the amount of just one primary color in the image

– Similar to color separations used in printing

– Darker areas contain less of that primary

– Lighter areas contain more

8 Bit & High Bit• Range of 256 possible values is called 8-bit

– 256 = 2 8 = ‘8 bits’

• High bit (RAW format only)– 4096 or more possible values per color channel– Same total dynamic range (gamut) – just finer distinctions– More information – less chance for posterization

Why is all this important?• 256 levels of color (per channel) provide enough information to

produce a smooth continuous tone image (16 million colors!)

• Anytime you modify or edit an image via your camera settings or on your computer you lose data!

• Moderate editing will not be noticeable• Excessive editing causes gaps in tones and a degraded (posterized)

image with loss of detail

What is editing?

• Changing tonality (levels)– Adjusting highlights or opening up shadows– Adjusting Contrast

• Adjusting hue or saturation• Changing white balance• Sharpening• Resizing (resampling)• Saving / resaving image in a lossy format (jpeg)• Just about any change you make in processing

your image destroys information

Camera Settings

Read Your Manual!

Practice shooting until using the Practice shooting until using the camera’s controls becomes camera’s controls becomes

second naturesecond nature

There’s no film or developing cost and There’s no film or developing cost and you can study the results immediately!you can study the results immediately!

Information on Equipment

• Rapidly changing field

• best place to get info is on the internet or in dedicated magazines– Dpreview.com, Outbackphoto.com, or

Luminouslandscape.com

Camera Settings: Image Size

• Image Size and Image Quality Menus– Terminology varies with models

• Large, medium, small (Fine, normal, basic)

– Sets the pixel dimensions of your image– Choose the largest size!– Choose the highest quality (least compression)!

Camera Settings: File Formats• What are they?

– Film Camera• Film both captures the image & stores it

– Digital Camera• The Photosensor captures the image• Digital Media (memory card) stores it• How it is stored (written) is called the ‘file format’

Major File Formats• JPEG (.jpg)

– Your camera settings (white balance, saturation, sharpness & contrast) applied by the camera before saving

– Uses a form of ‘shorthand’ called compression to make files smaller• RAW (.crw, .nef)

– Saves exactly what the imaging chip recorded• Camera settings are saved also – but separately

– Original data not altered– Processing of settings done later on computer– Uses high-bit data

Reasons to use JPEG

• Sufficiently good image quality

• Is the only option on some lower-end models

• Smaller file sizes -- more on a card / drive

• Files more easily transmitted online

• More efficient workflow– No post-processing conversion necessary

• Less time to write data to memory card– Important if you are using burst mode (taking

shots in quick succession)

JPEG Disadvantages• Uses only 8-bit data

– Less headroom for editing• Data has been permanently altered

– Camera settings can’t be changed without ‘double’ editing

• Compresses data– Data is lost each time file is saved– On large prints you might see compression artifacts

and loss of fine detail

No Compression Medium Severe Compression

Reasons to use RAW• Conversion into image done on computer

– more sophisticated algorithms than those in the camera for file linearization and color filter array (Bayer) conversion

• Flexibility– Can be processed multiple times using different settings

• No ‘double editing’ since each edit refers back to original data

– Ability to take advantage of future improvements in conversion technology

• Uses High-bit data– Greater editing latitude– Better able to extract shadow and highlight detail

• Often includes a JPEG– Adds advantages of JPEG format

Raw Disadvantages

• Large file sizes – 3 times the size of JPEG– Fewer images per memory card

• Longer write times to card

• Needs special software to convert to usable file type– post processing workflow more time consuming – Some skill required to get good results

RAW vs. JPEG

UnderexposedUnderexposedCorrected on computerCorrected on computer

OverexposedOverexposedCorrected on computerCorrected on computer

Compression & File Sizes

Format

File Size (MB)

File Size based on 5 megapixel image

TIFF 14.1 3 channels of 8 bits

RAW 7.7 1 channel of 12 bits

“Fine” or “Large” JPEG 2.3 Almost identical to uncompressed

“Normal” or “Medium” JPEG 1.3 Sufficient for 4”x6” print

“Basic” or “Small” JPEG 0.7 Sufficient for Web

File Formats: Summary• Use either RAW or JPEGUse either RAW or JPEG

– In normal situations – Either will produce a perfectly good image

• Use RAW (optimum quality)Use RAW (optimum quality)– In scenes with difficult exposure– With color problems (high saturation)– When extensive editing may be necessary

• more headroom to produce a better image– If you intend to make very large prints– For maximum control over your image

• Use JPEG (optimum performance)Use JPEG (optimum performance)– If you are producing a large number of images – Have time constraints– Outputting only to internet

Shooting Modes

• Mostly same as in film– Some additional ‘point & shoot’

presets– Offer nothing you can’t do

manually– Avoid using for serious work

• When you have the time use ‘manual’ mode for maximum control

• ‘Aperture’ or ‘shutter priority’ modes for quick action situations

Camera Settings: ISO

• Effectively, works the same way as in film speed• Ability to change on per shot basis• Only parameter not changeable after the fact in RAW

format• Higher settings can create noise

– Similar to grain in film– Less of a problem with higher-end cameras

Image NoiseTypes

– Luminance noise • Grayscale data• Grainy or patchy

– Color noise• Colored artifacts• Usually apparent in one channel

• How to Avoid– Use lowest possible ISO– Use higher shutter speed– Avoid digital zoom– Keep camera away from heat– Upgrade to a better camera

• Limited ability to fix with post- processing software– ‘Noise Ninja’, ‘Neat Image’, ‘Photoshop’

Camera Settings: Sharpening

• Digital captures not as sharp as film• Some sharpening is almost always needed• Do not let the camera determine the amount

– Set camera sharpening option to ‘zero’ or ‘off’• Sharpen on a computer monitor in post processing where

you can see what’s happening!

Camera Settings: Contrast & Saturation

• Better to perform these modifications in post processing where you can see it

• Non-reversible in JPEG format

• Set camera option for these to ‘zero’ or ‘off’

• Only use for speed and convenience

• Range of standard monitor

• Use for web output

• May be easier for beginners to match colors when printing

Color Space: The range of colors that a monitor or printer can reproduce

Camera Settings: Color Space

• Available on higher-end cameras• More information = More editing

room• Allows for prints with better color

reproduction

Visible SpectrumThe range of colors the human eye can detect

Note the greater ability to distinguish colors in the green range

Metadata

• Data on aperture, shutter speed, ISO, and most other camera settings saved permanently in image file

• Viewable in most photo editing programs

• Good for later analysis of your results

– What lens did you use to take that picture?

– What aperture did you use?

– What film speed?

– What time of day was it?

In the FieldIn the Field

Things That Haven’t Changed

f Stops & Shutter SpeedsExposure Modes

• Maybe a few new ones

Exposure BracketingDepth of Field

• Wider on some fixed lens cameras

Metering ModesFocusingFlash

Much

Memory Cards(Compact Flash, Removable Memory, Storage Card, etc)

• CapacityCapacity– Number of images they can hold

• Determined by:– Size of card, Camera megapixels, File format & Image quality

• Found on camera display screen

– Largest capacity not the best option• corruption or loss of full card would be catastrophic

– Size depends upon shooting style• Use a card that can hold what you would shoot in one session

• Write / Read SpeedWrite / Read Speed (measured in MB/per sec.)– Using a card that is faster than your camera is unnecessary expense– Hard to find specific camera write information

• www.robgalbraith.com/ for camera database

• Removing from cameraRemoving from camera– Make sure data-writing is finished before removing

• Always carry spare cardsAlways carry spare cards

Traveling• Need to store your image files so

you can empty & reuse your memory cards

• Available options– Laptop Computer

• Offers largest review of images• Can burn CD / DVD for backup• Takes up space• Highest-price option

– Stand-Alone Storage• Portable Hard Drive

– With or without LCD viewer screen– Various Capacities (20,40,80 GB)– Epson P2000, Flashtrax,Ipod, Delkin

• Portable DVD / CD Burner– Must carry blank cd /dvds

Batteries– Always carry spares– Limit use of LCD screen– Keep contacts clean

• Use clean pencil eraser• Both battery & compartment

– AA Batteries

• Nickel-metal hydride (Ni-MH) – most economical and longest lasting option

• NiCad– Drain completely to avoid ‘memory effect’

• Do not mix battery types• Replace as a set

Shutter Lag

• The time delay between pressing the shutter & when the image is recorded

• More of a problem with less expensive or older digital cameras

• To minimize, hold the shutter release button halfway down as you compose the shot; then press fully at the ‘right’ moment

Dust

• How to avoid– Shut off camera; wait 30 sec.

before changing lenses– Tilt body downward – Minimize time sensor is exposed

• How to Clean– Professional cleaning– Do it yourself

• Do not use compressed air• www.photosol.com/• http://copperhillimages.com/

– Correct each image in Photoshop• Clone tool, healing brush, dust &

scratches filter

Can be a problem with interchangeable lens cameras

Lenses: Quality

Film captures light

evenly across its surface

Digital sensor can lose

light near the edges

Use highest quality lenses or dedicated digital lenses

Optical vs. Digital ZoomOptical Zoom Digital Zoom

Enlarges image by adding new pixels in between the original ones

Results in a degraded image

Lenses: Focal length Magnification

• Subtle increase in DOF• Wide angle shots require

expensive super wide angle lenses

Film CameraNikon (1.5x FOV)

D100,D1x,D1H, D2H

Canon (1.6x FOV)

EOS 10D, Rebel

28 mm 42 mm 45 mm

85 mm 128 mm 136 mm

• Most digital cameras have sensors smaller than 35mm film

• Field of View crop

– Magnification Effect

Filters• Essential filters

– Skylight (to protect lens glass)– Polarizer

• Other filter effects can be done in post-processing– Pros: Won’t permanently alter image data– Can easily be fine-tuned or eliminated– Con: Learning curve and added workflow

FILTER PHOTOSHOP EQUIVALENT

Haze Unsharp mask 20,50,0

Color Correction White balance or color balance adj. layer

Warming (81,85)

Cooling (80, 82)Photo filter adj. layer

Graduated Neutral Density Shadow - Highlight adjustment

Enhancing Hue-Saturation adj. layer

LCD Screen• Composition Aid on Point & Shoot cameras

– Can preview image on P&S; but not on digital SLRs– Use with viewfinder– Of limited use in bright light– Can consume a lot of battery power

• Playback or review mode– Allows for instant analysis of images – Limited value in judging sharpness or exposure

• lightness & darkness of image changes with viewing angle • use histogram along with the playback/review image

– In camera editing• Avoid temptation to erase individual images from memory card• Erase entire card after it has been uploaded & backed-up

Digital Exposure

• Exposure latitude (dynamic range) similar to slide film• You can slightly underexpose

– 1/3 stop or more depending on contrast of scene– protect highlights from being blown-out– As you become familiar with the metering system on your

camera you can set exposure compensation before shooting– Verify exposure by checking the review histogram

• Exposure can be ‘refined’ in post processing software– ‘Clipped’ (blown-out) highlights can never be recovered!– ‘Clipped’ (filled-in) shadows are difficult to recover

Exposure Compensation(Recommendations of Katrin Eismann)

• Enter minus value in exposure compensation

• -1/3 stop: cloudy, low-contrast situations

• -1 stop: bright, contrast situations

• -1 1/3: extreme bright, sunny conditions

• Evaluate by checking histogram frequently

• Readjust to full tonality in Photoshop

Color TheoryPart 2

Just as you can describe a cake by Just as you can describe a cake by its ingredients; you can also its ingredients; you can also

describe it by its physical describe it by its physical characteristics: how it looks, its characteristics: how it looks, its

texture or the way it tastes. We’ve texture or the way it tastes. We’ve learned to describe colors by their learned to describe colors by their

ingredients, the 3 primaries. But ingredients, the 3 primaries. But colors also can be described by colors also can be described by

the way they appear. the way they appear.

Every color has three attributes …Every color has three attributes …

Understanding these attributes & how they interact will help Understanding these attributes & how they interact will help in the understanding of histogramsin the understanding of histograms

Hue

Predominant color: the rainbow or color wheel

Saturation

Value

HSV

The HistogramWhat is it?

A bar graph

What does it do?

Assigns each pixel a number based on its brightness (value)

Counts up the number of pixels of each value & displays them on the graph

The more pixels there are of any one tone; the higher the graph at that point

Why is luminosity important?

Most detail resides in the luminosity (brightness) of an imageNot in the hue differences

Good & Bad HistogramsLost shadow detail Good exposure Blown ‘Clipped’ Highlights

Evaluating the Histogram

No such thing as ‘perfect’ histogram– Different depending upon the content of the image– ‘Low Key’, ‘Low-Contrast’ & ‘High Key’ images

‘Expose to the Right’• Try to use as much of the right

side as possible– Lighter tones contains most of the

images data • the way photo-sensors work &

fundamental nature of f-stops

– Increase exposure (open up) as much as possible without clipping the highlights!!

• Most practical for landscapes, studio work

• Not practical in fast action photography

• Readjust dynamic range in Image Editing Software– Greater detail in highlights &

midtones

Types of Histograms• There are 2 types of

histograms– 1) Luminosity 1) Luminosity

HistogramHistogram• Measures brightness Measures brightness

(value) of image(value) of image• has some perceptual has some perceptual

compensationcompensation– Adjusted for the eye’s Adjusted for the eye’s

sensitivity for different sensitivity for different colorscolors

– Remember the green in Remember the green in the visible spectrumthe visible spectrum

• Does not show Does not show individual over individual over saturated channelssaturated channels

RGB Histogram• 2)2) R RGGBB Histogram Histogram

– Measures amounts of each primary: red, green, and blueMeasures amounts of each primary: red, green, and blue– Combines them into a composite histogramCombines them into a composite histogram– Somewhat better for evaluating exposureSomewhat better for evaluating exposure

• Alerts to oversaturated colorsAlerts to oversaturated colors

Luminosity vs. RGB

Determining which Histogram

• Your digital camera may show either a luminance or an RGB histogram

• Check your camera manual

• To determine which you have– Take a picture with your camera– Upload the image to your computer – Open it in your image editing program– Compare the RGB and luminance histograms in the

editing software to the camera’s histogram

Exposure Summary

• No perfect Histogram

• Capture full range of tones– Especially in the highlights

• Avoid ‘Clipping’ data

• Better to have slightly flat image than excessive contrast– Can be adjusted later

• Know what type of histogram your camera uses

White Balance

• In digital you adjust the ‘white balance’ to match different lighting situations

• Can be changed on a shot by shot basis

• 3 ways to set white balance

• Shooting film requires different films or filters for different lighting conditions– Daylight, Tungsten, Fluorescent

White Balance: Choice #1

• Camera Presets– Auto, sunlight, cloudy, fluorescent, incandescent,

etc– Set on camera and shoot– Not always accurate

• Light can change• Lens zoom can affect ‘auto’ setting

– Can be modified in post-processing• Involves double editing with JPEG files

White Balance: Presets Not Always Accurate

White Balance: Choice #2

• Use ‘Custom’ White Balance Setting– Take a shot of a sheet of white paper

• Fill entire frame with paper• Shoot under desired lighting condition

– Tell camera to use that shot to set white balance • Varies with camera makes & model• Usually set via menus

– More accurate than auto white balance– Must be changed for different lighting

White Balance: Choice #3• Use a digital white balance card

– Differs from a standard 18% gray card• 18% gray card has color cast in many lighting

situations• Good for setting exposure; not for setting white

balance• To use white balance card:

– Take shot of card under light conditions to be measured

– Continue shooting – Adjust in post processing (Photoshop

/Elements)• Use eyedropper in curves, levels, or raw

converter• Apply this adjustment to all other shots taken in

the same light• Brands

– Robin Myer’s Digital Gray Card• www.rmimaging.com

– WhiBal• www.rawworkflow.com

– Mini Color Checker• www.gretagmacbeth.com

Avoid using Pop-up Flash• Usually underpowered

– Not enough lighting for scene– Harsh transitions between dark

& light

• Little control over light levels• No control over lighting

angles• Longer lenses may block light

– Shadow across bottom of image

• In some venues it may be your only option

Burst Mode• Ability to take several shots immediately one after

another– similar to a film SLR camera with a motorwind

• Number of frames per second & total number of frames differs greatly among camera models

• Larger memory cards / spare batteries

Taking Advantage of DigitalTricks &Techniques

Extending Dynamic RangeWhen tonal range of scene exceeds the

capacity of the camera

• Use a good tripod & cable releaseUse a good tripod & cable release

• Take one exposure for highlights and one Take one exposure for highlights and one for shadowsfor shadows

• Use aperture priority Use aperture priority – Changing aperture can change focus and Changing aperture can change focus and

DOF – images won’t match upDOF – images won’t match up– Vary shutter speed insteadVary shutter speed instead

• Combine in photo editing softwareCombine in photo editing software

Panoramas

• Use a good tripod & cable releaseUse a good tripod & cable release– Stay level -- Use bubble level on hot shoeStay level -- Use bubble level on hot shoe

• Use a ‘normal’ focal length lens for more natural perspectiveUse a ‘normal’ focal length lens for more natural perspective• Overlap images approx. ¼ of frameOverlap images approx. ¼ of frame• Maintain same aperture and focusMaintain same aperture and focus• Shoot Vertical FramesShoot Vertical Frames

– More ‘frames’ but less perspective distortionMore ‘frames’ but less perspective distortion

Panoramas• Choose scene with even illuminationChoose scene with even illumination• Maintain consistent white balanceMaintain consistent white balance

– Do not use auto white balanceDo not use auto white balance– Use custom white balanceUse custom white balance– Shoot in RAW formatShoot in RAW format

• No polarizerNo polarizer– Creates color changes near edge of each Creates color changes near edge of each

frameframe

• Minimize parallax problemsMinimize parallax problems– Keep foreground elements to a minimumKeep foreground elements to a minimum– Use panorama head (www.reallyrightstuff.com)Use panorama head (www.reallyrightstuff.com)

• Combine in post processing softwareCombine in post processing software– Photoshop CS, CS2 ‘Photomerge’Photoshop CS, CS2 ‘Photomerge’– ‘‘Stitching’ softwareStitching’ software

Stitching Super Images

Images © Max Lyons

Used with permission of the artist

Images created with his PTAssembler software available at http://www.tawbaware.com/maxlyons/index.html

Shooting CompositesTo eliminate distracting elements

Shooting Composites

Depth of Field Composites

• Use tripod

• Take several exposures

• Change focus with each exposure

• Use smallest aperture for all exposures

• Use manual focus

• Subject must not move

Too few exposures and image elements may not align

properly

When You Get Back Home

• Make a duplicate (backup) folder – On second hard drive, CD or DVD

• Put memory card back into camera– Empty card in camera

• Either ‘delete all images’ or ‘format card’• Never format card on the computer

• Upload entire card to computer– Create a folder for the new

images on your hard drive– Use memory card reader to

transfer images• Acts as an external hard

drive• Uploading directly from

camera drains camera batteries

Sources

InternetDigital Photography Review -- http://www.dpreview.com/Binary Converter -- http://nickciske.com/tools/binary.phpWhiBal -- http://www.rawworkflow.com/Digital Darkroom -- http://www.timgrey.com/ddq/Ximina’s Photography -- http://www.ximinasphotography.com/123di.com -- http://www.123di.com/Max Lyons -- http://www.tawbaware.com/maxlyons/index.htmlBattery University -- www.batteryuniversity.com

PrintReal World Photoshop -- David Blatner & Bruce FraserDigital Photography -- Katrin Eismann, Sean Duggan & Tim GreyCamera Raw With Adobe Photoshop -- Bruce FraserHow Digital Photography Works – Ron WhiteShooting with Maximum Feedback: Photoshop User Magazine -- Kevin Ames