# "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.

## Presentation on theme: ""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."— Presentation transcript:

"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 Digital Theory & Technique Image Essentials Color Theory Camera Settings File Formats ISO White Balance Color Space Digital Exposure Histogram Panoramas Composites Traveling Shooting Problems

Warning The following program contains: Graphic Images Abstract Concepts Mild Mathematics Viewer Discretion is Advised

Image Essentials

The Digital Image The Pixel A 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 series of numbersTo your computer, each pixel is really only a series 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 = 0011001000110011001110000010 0000001100010011001000111000 0010000000110010001100010011 0111 One pixel What you see What Photoshop sees What Photoshop sees What your computer sees What your computer 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? 24 256

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 Theory Just as a cake can be described by the relativeamounts of sugar, flour, eggs, it contains, so a pixel’s color is described by the proportions of its ingredients: the 3 primary colors Just as a cake can be described by the relative amounts of sugar, flour, eggs, it contains, so a pixel’s color is described by the proportions of its 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 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 camera’s controls becomes second nature There’s no film or developing cost and you can study the results immediately! There’s no film or developing cost and 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 Underexposed Corrected on computer Underexposed Corrected on computer Overexposed Corrected on computer Overexposed Corrected on computer

Compression & File Sizes Format File Size (MB) File Size based on 5 megapixel image TIFF14.13 channels of 8 bits RAW7.71 channel of 12 bits “Fine” or “Large” JPEG2.3Almost identical to uncompressed “Normal” or “Medium” JPEG1.3Sufficient for 4”x6” print “Basic” or “Small” JPEG0.7Sufficient 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 Noise Types –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 Spectrum The 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 Field

Things That Haven’t Changed f Stops & Shutter Speeds Exposure Modes Maybe a few new ones Exposure Bracketing Depth of Field Wider on some fixed lens cameras Metering Modes Focusing Flash 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 databasewww.robgalbraith.com/ 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

Tethering Feedback on LCD screen of limited value More accurate is a direct hook-up to computer –Desktop computer for studio work –Laptop for on location shooting Allows direct shooting to hard drive –Greater storage for images Ability to see and fine tune images immediately Requires special software –Nikon Capture –Capture one Pro –Bibble Pro Only applicable for certain types of photography

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 Zoom Optical 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 Camera Nikon (1.5x FOV) D100,D1x,D1H, D2H Canon (1.6x FOV) EOS 10D, Rebel 28 mm42 mm45 mm 85 mm128 mm136 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 FILTERPHOTOSHOP EQUIVALENT HazeUnsharp mask 20,50,0 Color CorrectionWhite balance or color balance adj. layer Warming (81,85) Cooling (80, 82) Photo filter adj. layer Graduated Neutral DensityShadow - Highlight adjustment EnhancingHue-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 Theory Part 2 Just as you can describe a cake by its ingredients; you can also describe it by its physical characteristics: how it looks, its texture or the way it tastes. We’ve learned to describe colors by their ingredients, the 3 primaries. But colors also can be described by the way they appear. Every color has three attributes … Understanding these attributes & how they interact will help in the understanding of histograms

Hue Predominant color: the rainbow or color wheel

Saturation

Value

HSV

The Histogram What is it? A bar graph What does it do? A ssigns 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 image Not in the hue differences

Good & Bad Histograms Lost 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 Histogram Measures brightness (value) of imageMeasures brightness (value) of image has some perceptual compensationhas some perceptual compensation – Adjusted for the eye’s sensitivity for different colors –Remember the green in the visible spectrum Does not show individual over saturated channelsDoes not show individual over saturated channels

RGB Histogram 2) RGB Histogram2) RGB Histogram –Measures amounts of each primary: red, green, and blue –Combines them into a composite histogram –Somewhat 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 Digital Tricks &Techniques

Extending Dynamic Range When 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 for shadowsTake one exposure for highlights and one for shadows Use aperture priorityUse aperture priority –Changing aperture can change focus and DOF – images won’t match up –Vary 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 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 distortion

Panoramas Choose scene with even illuminationChoose scene with even illumination Maintain consistent white balanceMaintain consistent white balance –Do not use auto white balance –Use custom white balance –Shoot in RAW format No polarizerNo polarizer –Creates color changes near edge of each frame Minimize parallax problemsMinimize parallax problems –Keep foreground elements to a minimum –Use panorama head (www.reallyrightstuff.com) Combine in post processing softwareCombine in post processing software –Photoshop CS, CS2 ‘Photomerge’ –‘Stitching’ 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 http://www.tawbaware.com/maxlyons/index.html

Shooting Composites To 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 Internet Digital Photography Review -- http://www.dpreview.com/http://www.dpreview.com/ Binary Converter -- http://nickciske.com/tools/binary.phphttp://nickciske.com/tools/binary.php WhiBal -- http://www.rawworkflow.com/http://www.rawworkflow.com/ Digital Darkroom -- http://www.timgrey.com/ddq/http://www.timgrey.com/ddq/ Ximina’s Photography -- http://www.ximinasphotography.com/http://www.ximinasphotography.com/ 123di.com -- http://www.123di.com/http://www.123di.com/ Max Lyons -- http://www.tawbaware.com/maxlyons/index.html http://www.tawbaware.com/maxlyons/index.html Battery University -- www.batteryuniversity.comwww.batteryuniversity.com Print Real World Photoshop -- David Blatner & Bruce Fraser Digital Photography -- Katrin Eismann, Sean Duggan & Tim Grey Camera Raw With Adobe Photoshop -- Bruce Fraser How Digital Photography Works – Ron White Shooting with Maximum Feedback: Photoshop User Magazine -- Kevin Ames

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