Keys to Sharper Images - Teton Photography Group

Keys to Sharper Images - Teton Photography Group
1/18/2016
PHOTOGRAPHY:
TRICKS OF THE TRADE
• Poor composition
• Lack of subject, foreground, background
• Clutter and distractions
• Improper exposure
Techniques to make you shine
Loren Nelson
www.NaturalPhotographyJackson.com
• Over-exposure
• Under-exposure (sometimes fixable in PP)
• Unintentionally blurred image
• Out of focus / improper depth of field
• Subject moves too fast for set shutter speed
• Camera shake
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Welcome and introductions
Overview of general problems in photography
Review components of exposure
Review problems reducing sharpness
How to improve camera stability
How to control subject motion
How to improve focus / sharpness
Wrap-up by 8 PM
• At the end of this session, you will be able to:
• Identify the possible causes of a blurred image
• Determine the most like cause for blurring of a
specific image
• List means to minimize camera shake
• List means to optimize camera focus
• Understand techniques to control subject motion
• Identify post-processing tools to sharpen image
• Obtain sharper images
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• Type (phone, Point-and-shoot, super-zoom, mirrorless (MILC),
Single lens reflex (dSLR)
• Brand
• Shooting modes – Auto, Program, A, S, Manual, Bulb
• Image capture - RAW or JPEG
• Sensor – size, pixels, resolution, sensitivity, digital noise
• ISO range
• Shutter speed range
• Burst rate
• Other bells and whistles
• RAW files (.CR2, .NEF)
• Large file size
• Non-viewable image data
• EXIF and other metadata and JPEG thumbnail
12 – 14 bit
4,096 – 16,384
levels
• DNG (Adobe, .DNG)
• Smaller file size (Adobe, non-proprietary)
• Non-viewable, slightly compressed image data
• No .XMP side-car file needed
• JPEG images
• Highly compressed, much smaller image file
• Edited by camera/software
• Each save loses data
8 bit
256 levels
Luminance levels (brightness) per RGB channel
Generally, more pixels give higher resolution
More pixels per sensor area means smaller pixels
Smaller pixels need more light and create more noise
If two sensors have the same digital noise at 100%,
the sensor with the most pixels will produce a cleaner
image
• 8-12 megapixels give far more resolution than
needed for web posts and viewing (72 ppi)
• 22 megapixels will yield 14x22 print at 240dpi
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Three elements control exposure
ISO sets sensor sensitivity
ISO
Aperture controls amount of light
Shutter speed controls duration of exposure
Aperture
Shutter speed
Any change in one factor requires an equal and
opposite sum change in the other two factors
One “stop” or EV (exposure value) implies a doubling or halving of exposure.
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• Your tripod is your most important accessory
• Tripod
• Prime or zoom
• Focal length (mm)
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• Angle of view
• “Reach”
• Magnification
• Maximum aperture (f-stop)
• Head
• “Speed”
All can affect
sharpness
• Focusing speed
• Image stabilization
• Minimal focus distance
100mm lens = 1/100th sec
• Minimum shutter speed = 1/focal length of lens
• Crop sensor modification? 1/focal length x crop
factor
100mm lens = 1/150th sec
• Image stabilization (IS) may add 2-3 stops (EV)
Vibration reduction (VR)
Aluminum versus carbon fiber
Height – maximum and minimum; weight
Stability
Leg sections, locks, elevator, and other features
100mm lens = 1/25th - 1/50th sec
• Pan (3 axis) head, ball head, or gimbal
• Quick connect – ARCA Swiss versus proprietary
• Monopod and other stabilization devices
• Spend the money now or spend more later!
• Quality tripod and head
• Size and weight
• Aluminum versus carbon fiber
• Heads
• Pan and tilt – three planes
• Ball head
• Gimbal head
• Other stabilization – monopod, bean bag, window mount, rifle-stock,
noodle, Gorilla-pod
• Proper hand-held technique
• Image stabilization (in lens or some cameras)
• Not used under certain conditions
“Camera shake”
• Mirror lock-up or timer with long lenses
• Remote shutter release
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High f-stop
Small aperture
Wide depth of field
Slow shutter speed
Star-effect in bright light
Motion effects
Defraction softening
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Low f-stop
Large aperture
Narrow depth of field
Fast shutter speed
Freeze action
Minimize camera shake
Corner softening
• Lens focuses on a single plane – parallel to the sensor
• A range of “acceptable” focus occurs on each side of the plane
• Rule of thumb – 1/3 in front and 2/3 behind plane of focus
Only a rule of thumb!
Actual acceptable focus
varies with the lens, its
focal length, and the
focusing distance
• Distance between nearest and farthest objects that are in
acceptable focus
• Precise focus is at a single point in a plane
• Any plane nearer or farther the light point on the sensor will
appear as a circle
• When focus of the circle is sufficiently small to appear to be a
single point, we say focus is acceptable
• The actual size of the circle is called the “circle of confusion”
• The distance of the subject that yields an acceptable circle of
confusion (i.e., a point) before and behind precise focus is the
depth of field
• Image magnification
• How the camera “sees” the subject
• Sensor size – larger = more DoF
• Effective focal length – longer = less DoF
• Distance – closer = less DoF
• Aperture
• Set f-stop
• Larger opening (lower f number) = less DoF
http://digital-photography-school.com/
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• The minimum distance beyond which everything is in
acceptable focus
• Sensor size (Crop Factor)
• Focal length
• Aperture
• Assume high quality lens
• Full-frame camera defraction-limited at smaller than f/22
• APS-C sensor defraction-limited at smaller than f/16
• Minimal with large aperture
• Potential problem with small aperture
• Depends upon sensor size
f/2.8
• Full frame above f/22
• APS-C above f/16
• Result is lower resolution
• Softer image
• Maybe compounded by slow shutter
speed
Pro high (fast) shutter speed
• Freeze action
• Minimize camera shake
• Large aperture so narrow
depth of field
• Need higher ISO
f/22
Con low (slow) shutter speed
• Blur image for motion effect
• Smaller aperture so greater
depth of field
• Can use lower ISO
ISO
Aperture
Shutter speed
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For every positive, there is a negative
Aperture
Shutter
Speed
Digital
Noise
Depth of
Field
Depth of
Field
Motion
Blur
Shutter
Speed
Digital
Noise
ISO
Diffraction
Camera
Shake
• Number of focusing points
• Type of focus points
• Phase detect vs contrast detect
• Cross-type vs horizontal or vertical
Depth of
Field
And on and on…
• Move autofocus from shutter release to thumb
• Locks focus so can recompose and shoot
• Modes of focus control
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Manual
Single point (spot, expansion)
Zone / multipoint
One shot (AF-S)
AI Servo (Continuous; AF-C)
AI Focus – blend (AF-A)
• Autofocus assist beam (“active” AF)
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• Designed to reduce vibration caused by “mirror slap”
• When activated, press shutter release once to lock
mirror and press again to activate shutter
• Use only on tripod
• Other options:
• Two second delay
• Live View mode
• Intentional blur
• Slow shutter speed
• May need stabilization (tripod)
• Panning
• Blurs the background and not the subject
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Exposure / luminosity – intensity of light
Contrast / tonality – range of luminosities
Saturation (intensity of color)
White balance
Level and crop
Sensor dust
Distractions
Digital noise reduction
Sharpen
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Not really sharpening
Local contrast adjustments of “edges”
Noise reduction / sharpening paradox
Lightroom or CameRaw clarity slider
Lightroom or CameRaw sharpening
Photoshop sharpening tools
• High-pass filter, Smart Sharpen, unsharpen mask, other filters, other
• Blur simulation filters (many in PSCC)
• Other software sharpening tools & plug-ins
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• Low light situations
• Longer shutter speed – more camera shake
• Long telephoto / super-zoom lens
• More ‘magnification’ of camera shake
• Extreme close-up / macro
• Extremely shallow depth of field
• More ‘magnification’ of camera shake
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Focus stacking software
Merge multiple overlay images at sharpest points
Stable tripod necessary +/- focus rail (for macro)
Photoshop
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Select images (Edit in Photoshop as layers); Select all layers
Auto-align images
Auto-merge images
Edits, flatten layers?, save, close
• Helicon Focus
• Controls the camera and creates series of layered images
• Merges at sharpest points
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Camera stabilization
Appropriate lens
Appropriate shutter speed
Appropriate aperture for desired DoF
Choose best focusing mode
Always consider best motion blur for moving subjects
Apply noise reduction and sharpening in postproduction
• Good photographs
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Proper exposure
Sharp focus
Nice composition
Good subject
• Great photographs
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Emotional impact / visual tension
Creativity and style
Feeling and emphasis
Seeing and understanding
Unique perspective / lighting
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