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Making Trail Images with a What are star trails? Digital Camera • The position of the in the Heavens Victor Dallons are fixed. Doug Hall • As the turns, they appear to move.

• A long shows the path the stars take through the sky.

© 2017 Victor Dallons & Douglas Hall 1 Photo by Victor 2Dallons

Approach Approach images are made by: Star trail images are made by: • Film: • Digital: – Taking an ~hour long exposure of the – Taking multiple ~30 sec exposures taken over an extended period of time, usually about 1 hr. • Digital: – Combining the multiple images in post – Taking an hour long exposure on a digital processing (Stacking). camera may overheat sensor. • Stacking - images are placed one on top of another and the brightest points accumulated in • Increases noise the final image • May burn out sensor

Photo by Doug Hall 3 Photo by Doug Hall 4

Stacking Demo Approach

! Stacking multiple digital images allows greater flexibility in setting exposures.

" With an hour long exposure, you must shoot in a dark location to avoid over exposing or blowing out the foreground.

5 Photo by Doug Hall 6

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Approach Approach

! Stacking multiple digital images allows • Prepare equipment. greater flexibility in setting exposures. • Check equipment operation. • Select a composition. " Stacking multiple exposures allows better – Scene control of foreground exposure. – Appearance or look ! Can shoot with higher ambient light levels. • Make exposure(s) ! Can use light painting to highlight foreground. • Post processing: ! Can also employ High Dynamic Range (HDR) – RAW development techniques. – Stacking

Photo by Doug Hall 7 Photo by Doug Hall 8

Equipment Equipment

• Tripod • Lens that works best for your scene • Freshly charged battery and spare • Camera capable of: • Empty memory card – Manual exposure settings • Small flashlight, headlamp – Ability to automatically time consecutive exposures • Larger flashlight for light painting • Intervelometer (Built in camera or external) • Warm clothes • Cable release with a setting and continuous release mode on camera • Camp chair

Photo by Doug Hall 9 Photo by Doug Hall 10

Intervelometer vs Con?nuous Release Intervelometer vs Con?nuous Release • Intervelometer: – Advantages: • Longer than 30 sec exposures possible. – May require an external intervelometer. – More flexibility balancing light of scene with sky • With built in, no need to purchase cable release. – Disadvantages: • Intervelometers are expensive • Setup can be difficult. – Account for time to store image – May leave about a 3 sec gap between exposures resulting in dashed lines.

Photo by Doug Hall 11 12

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Intervelometer vs Con?nuous Release Preparation • Continuous Release: • Know how to operate your camera in – Advantages: the dark. • Simple to set up. – Know the location of all controls by feel. • Check out operation of interval timer – Disadvantages: beforehand. • Limited to less than 30 sec exposure. • Scout your locations and compositions in the daylight.

Photo by Doug Hall 13 Photo by Doug Hall 14

Shooting Conditions Camera Settings • Turn OFF • Clear Skies ! high ISO noise reduction (jpg images) • Some ambient light from moon or street ! long exposure noise reduction lights to light scene is OK. ! mirror lockup, timer delay • Can take pictures during nautical twilight ! vibration reduction – More stars visible as it becomes darker • Focus set to manual • Low dew point • Remove filters such as UV filter. – Lens may fog over part-way through – Reduces chance of lens flare from lights exposures. • Drive set to high continuous

Photo by Doug Hall 15 Photo by Doug Hall 16

Camera Settings Camera Settings • White Balance • File Format – NA if shooting RAW, adjust in post processing. – Shooting in RAW: – When shooting jpg, after nautical twilight, • Advantages: approximate sky color will be from black to: – Can adjust WB, exposure, etc in RAW processor • Disadvantage – Some stacking software do not take RAW files: WB = Auto WB = Daylight WB = Tungsten WB = Fluorescent » Must convert files to .jpg or .tiff format. ! Shooting in jpg: ! Advantages: ! Can dump directly into stacking software ! Disadvantage: ! Can’t adjust white balance, exposure, etc. 17 Photo by Doug Hall 18

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Camera Settings Camera Settings • Set camera to Manual mode • ISO set for desired exposure • speed at 30 seconds (Continuous) ! In dark areas, start at ISO 400 – 800 • f stop appropriate for scene ! Adjust for ! density (number of) of stars desired ! f/4 to f/11 ! lightness of sky ! can be adjusted in post processing – Take test images and look for stars.

Photo by Doug Hall 19 Photo by Doug Hall 20

Ligh?ng Examples Ligh?ng Examples

• Dark Skys • Full Moon lit scene

Star Streak in Arches 1 hr f/4 ISO 1600 Sedona Star Trails 1.3 hr f/4 640 ISO 150 mm focal length cropped sensor Photo by Doug Hall 21 Photo by Victor Dallons22

Camera Settings Ligh?ng Examples

• ISO set for desired exposure • Urban Scenes ! In urban settings, adjust ISO to about 1 to 2 – Foreground lighting stops overexposed when metering on sky. provided by ! This setting increases the brightness of stars gas station ! Sky may look grey on camera back across street. ! Sky darkness will be adjusted in post processing – Files must be in RAW – Take test images and look for stars.

Nyholm Windmill 1 hr f/8 800 ISO 24 mm focal length cropped sensor Photo by Doug Hall 23 Photo by Victor Dallons24

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Ligh?ng Examples Ligh?ng Examples

• Cityscapes • Cityscapes – RAW file appearance

San Francisco Star Trails 2 hr f/11 800 ISO 32 mm cropped sensor San Francisco Star Trails 1 hr f/11 800 ISO 32 mm cropped sensor Photo by Victor Dallons25 Photo by Victor Dallons26

Camera Settings Camera Settings - Advanced

• ISO and noise ! Balancing foreground/background – Image stacking inherently reduces noise. exposures • Stacking 4 images cuts the noise in half ! Dark foreground • Stacking 16 images cuts the noise to ¼ ! Set ISO for foreground • Stacking 120 images (1 hr) cuts the noise by 1/11th " Darken sky in post processing • Stacking 256 images cuts the noise to 1/16th • limited to several stops – Considering stacking noise reduction, keep ! HDR " Use long exposure on one image – 5 min or more your ISO low enough to avoid noise. ! Use intervelometer with all long exposures. • Noise levels in light painted areas will be greater ! Light Painting than in the sky. • Know the noise levels in your camera. 27 28

Camera Settings - Advanced Camera Settings - Advanced

• Balancing foreground/background • Stars have color exposures • Light Foreground (City Scape) – Set ISO for stars. – HDR (Make exposures at start) – Split neutral density filter for water reflections (5 stops)

SeaTle Stars 120 min f/5.6 400 ISO 28 mm focal length cropped sensor Photo by Victor Dallons29 30

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Star Trails Total Exposure Duration

• Total Exposure Duration • Focal length impacts length of star trails – Star trails will appear longer with telephoto – Usually about 1 hr duration lens – Longer times for longer trails • Will also increase density of star trails • Time needed for star trail to cover ¼ of frame on diagonal DX Focal length 11 13 16 23 33 47 57 67 133 200 FF Focal length 16 20 24 35 50 70 85 100 200 300 Hours 1.8 1.6 1.4 1.0 0.8 0.6 0.5 0.4 0.21 0.14

Photo by Doug Hall 31 Photo by Doug Hall 32

Focusing Composition

• Focusing after dark is difficult. • Large sky • Focus at infinity or use hyperfocal distance. • Interesting foreground / mid-ground • Focusing approaches: – Consider light painting – Set up before dark and focus then • Density of stars preferred – Focus on bright object such as distant lights, moon, etc, – Adjust ISO and cumulative exposure time – Bring a powerful light to temporarily light your – Can make adjustments in post processing. mid-ground subject. – Greater star density higher above horizon. – Trial and error. • Think about direction of star movement. • Set focus to manual

Photo by Victor Dallons33 Photo by Doug Hall 34

Star Trail View Direc?on Star Trail View Direc?on West North West

ScaTer Creek Star Trails 1 hr f/2.8 400-800 ISO 24 mm focal length full frame Photo by Doug Hall 35 Nyholm Windmill 1 hr f/8 800 ISO 24 mm focal length cropped sensor Photo by Victor Dallons36

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Star Trail View Direc?on Star Trail View Direc?on North North East

Sparks Lake Star Trail 1 hr f/2.8 3200 ISO 16 mm focal length full frame SeaTle Stars 120 min f/5.6 400 ISO 28 mm focal length cropped sensor Photo by Doug Hall 37 Photo by Victor Dallons38

Star Trail View Direc?on Star Trail View Direc?on East South East

Bernal Heights Trees 30 min f/8 800 ISO 100 mm focal length cropped sensor 39 Mt St Helens Star Trails 1 hr f/4 400-800 ISO 20 mm focal length full frame Photo by Doug Hall 40 Photo by Victor Dallons

Star Trail View Direc?on South • Use an Light Pain?ng incandescent bulb flashlight to add warmth. • Length of time light is on is trial and error, depending on strengthe of light and camera settings. • Paint several frames to even out light.

Hot Shop Reflec?ons 50 min f/4 800 ISO 24 mm focal length cropped sensor 41 Photo by Doug Hall 42 Photo by Victor Dallons

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Light Pain?ng - Stacking Start Simple • Use an LED flashlight for cooler light. • Length of time light is on is trial and error, depending on strength of light and camera settings. • Start Simple • Paint several frames to even out light – Go into backyard or park and shoot straight up to test out your technique. • Go through entire process – shooting through post processing. – Start with simple compositions in dark areas. • Advance to more complicated lighting situations.

Old House 70 min f/8 800 ISO 34 mm focal length cropped sensor Photo by Victor Dallons43 Photo by Doug Hall 44

Post Processing Star Trails - Post Processing ! Multiple images need to be combined to ! Star Stacking program make up final image. ! Suggest trying StarStaX ! 1 hr exposure has about 120 thirty second ! http://markus-enzweiler.de/StarStaX/StarStaX.html segments to combine. ! Advantages ! Images are combined by Stacking ! Very fast ! 2 general approaches: ! Can add some special effects. ! Don’t need photoshop or elements ! Star Stacking program ! Disadvantages ! Manual stacking in Elements or Photoshop ! Includes temporal distractions in final image ! RAW images must be converted to tiff or jpg first. ! Can convert in Lightroom as a batch process.

Photo by Doug Hall 45 Photo by Doug Hall 46

Star Trails - Post Processing RAW File Development ! Manual stacking in Photoshop or Elements • To darken sky while retaining stars: ! Advantages ! Can remove temporal distractions such as airplanes. – Set black point with “blacks” slider ! Can work with processed RAW files. – Increase contrast with “contrast slider” ! Disadvantages – Adjust “exposure” for number of stars visible ! Time consuming and tedious to handle many images – Do not use clarity ! Requires photoshop, elements, or other software that have layers. – Can also use curves to darken skies. • Set color of sky to your preference with “temperature” and “tint” sliders • Do not apply noise reduction

Photo by Doug Hall 47 48

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Preparing for Stacking Photoshop Stacks

• Lightroom • In Photoshop, select all layers and change – Export files as ?ff files blending mode to “lighten” • Retains 16 bit informa?on • To delete airplane trails: • Photoshop/Bridge – Find the layer that contains the airplane trail – Load layers into Photoshop from Bridge – Paint the airplane trail with black. • Menu: Tools/Photoshop/Load files into Photoshop layers • Sharpening – Suggest working in batches of 40 – 50 files, – Aaer flaTening the layers: flaTening the stack, and saving as a sub collec?on. • Duplicate the layer, set layer blend mode to “lighten”, Then combine the sub-collec?ons the same way as then sharpen. the individual files. • Sharpening will increase the brightness of the star trails. 49 50

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