Play Video
1
Blurred backgrounds Depth of Field Explained
Blurred backgrounds Depth of Field Explained
::2011/07/07::
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2
Product Photography : How ISO Affects Depth of Focus
Product Photography : How ISO Affects Depth of Focus
::2008/08/31::
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3
Depth Of Field Explained Part 1 - short lens
Depth Of Field Explained Part 1 - short lens
::2012/10/15::
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4
PROOF of Holographic Moon Projection - Depth of Focus
PROOF of Holographic Moon Projection - Depth of Focus
::2014/01/05::
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5
Listen-Depth Of Focus
Listen-Depth Of Focus
::2011/03/13::
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6
Lecture 26 Depth of focus and field; polarization; wave plates
Lecture 26 Depth of focus and field; polarization; wave plates
::2014/05/26::
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7
Tutorial - Audio Visual - Focus & Depth of Field
Tutorial - Audio Visual - Focus & Depth of Field
::2013/05/15::
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8
AFTER EFFECTS DEPTH OF FIELD - CAMERA FOCUS
AFTER EFFECTS DEPTH OF FIELD - CAMERA FOCUS
::2010/08/16::
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9
"Wash Day" - Depth of focus experiment by Richard Stewart
"Wash Day" - Depth of focus experiment by Richard Stewart
::2013/12/27::
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10
CC-V Depth of Focus and Field of View
CC-V Depth of Focus and Field of View
::2013/07/30::
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11
Depth Of Focus Test (After Effects)
Depth Of Focus Test (After Effects)
::2013/06/06::
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12
SONITUS Project Depth of focus
SONITUS Project Depth of focus
::2009/11/04::
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13
Depth of focus with a Cognex DataMan 500
Depth of focus with a Cognex DataMan 500
::2012/06/29::
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14
Photoshop Tutorial - Depth of Field Effect (out of focus background) - HOW TO
Photoshop Tutorial - Depth of Field Effect (out of focus background) - HOW TO
::2012/09/23::
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15
Sony VG20 depth of focus.mp4
Sony VG20 depth of focus.mp4
::2012/01/26::
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16
Depth of focus test
Depth of focus test
::2010/08/26::
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17
Photoshop Elements 11 Create Soft Focus and Depth Of Field
Photoshop Elements 11 Create Soft Focus and Depth Of Field
::2012/12/28::
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18
Creating Depth of Field using Rack Focus in Adobe Premiere Pro
Creating Depth of Field using Rack Focus in Adobe Premiere Pro
::2009/10/22::
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19
Photography Tips - Focal Length Changes 3 Things - Focal Length Explained 2
Photography Tips - Focal Length Changes 3 Things - Focal Length Explained 2
::2012/10/07::
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20
Depth of focus- Silent (Live at Kuch Khaas)
Depth of focus- Silent (Live at Kuch Khaas)
::2011/02/26::
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21
Defocus of the camera (Depth of focus) - Made with Blender 3D
Defocus of the camera (Depth of focus) - Made with Blender 3D
::2010/02/13::
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22
Canon Rebel T3i Depth Of Field and Focus Test
Canon Rebel T3i Depth Of Field and Focus Test
::2011/10/29::
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23
Depth of Focus Showreel
Depth of Focus Showreel
::2007/03/04::
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24
Sony A33/A55 VIDEO deep focus / depth of focus /  (Schärfentiefe - Tiefenschärfe)
Sony A33/A55 VIDEO deep focus / depth of focus / (Schärfentiefe - Tiefenschärfe)
::2010/10/09::
Play Video
25
Depth of focus- Change
Depth of focus- Change
::2010/10/06::
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26
lightwave animation tutorial - focus and depth of field
lightwave animation tutorial - focus and depth of field
::2010/04/13::
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27
Depth Of Field Exercise
Depth Of Field Exercise
::2012/10/15::
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28
Creating Depth of Field using Rack Focus - Avid Forums version
Creating Depth of Field using Rack Focus - Avid Forums version
::2012/11/26::
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29
Focus Pulling / Depth of Field Test - Canon T3i/600D
Focus Pulling / Depth of Field Test - Canon T3i/600D
::2012/12/20::
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30
Blender 2.69 -   Animating a Curve and Depth of Field Focus
Blender 2.69 - Animating a Curve and Depth of Field Focus
::2013/11/15::
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31
How to use Depth of Field (Focus Shifting)
How to use Depth of Field (Focus Shifting)
::2014/02/23::
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32
3ds Max Depth Of Field
3ds Max Depth Of Field
::2012/12/11::
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33
Cinema 4D camera Properties - Depth of Field, Focus Distance and others - Cinema 4D camera Tutorial
Cinema 4D camera Properties - Depth of Field, Focus Distance and others - Cinema 4D camera Tutorial
::2014/03/18::
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34
How to Make Depth of Field or Focus in Sony Vegas Pro 13-8
How to Make Depth of Field or Focus in Sony Vegas Pro 13-8
::2014/08/06::
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35
Education from Michael on Depth of Focus
Education from Michael on Depth of Focus
::2012/06/08::
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36
Putting background out of focus Nikon Canon
Putting background out of focus Nikon Canon
::2010/09/24::
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37
out of focus and blurriness explained
out of focus and blurriness explained
::2014/05/18::
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38
Creating Depth of Field using Rack Focus in Avid Media Composer
Creating Depth of Field using Rack Focus in Avid Media Composer
::2012/11/26::
Play Video
39
DEPTH OF FIELD HX1 MANUAL FOCUS
DEPTH OF FIELD HX1 MANUAL FOCUS
::2010/10/06::
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40
5d Mark II + 85mm F1.8 Depth of Focus preview
5d Mark II + 85mm F1.8 Depth of Focus preview
::2010/03/17::
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41
Narrow Depth of Focus Test 2
Narrow Depth of Focus Test 2
::2010/01/11::
Play Video
42
Expand your Depth of Field (DOF) Focus Stacking in Photoshop
Expand your Depth of Field (DOF) Focus Stacking in Photoshop
::2013/08/20::
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43
FUJIFILM Finepix HS20 EXR Manual Focus & Depth of Field in Video Test
FUJIFILM Finepix HS20 EXR Manual Focus & Depth of Field in Video Test
::2012/02/23::
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44
Depth of Field using manual focus
Depth of Field using manual focus
::2014/03/28::
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45
Sony hx 300 - Test of Zoom, macro and focus tracking, depth
Sony hx 300 - Test of Zoom, macro and focus tracking, depth
::2013/04/27::
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46
Using Cameras - Focus/Depth of Field
Using Cameras - Focus/Depth of Field
::2013/02/04::
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47
Depth of Field - The Three Rules | Photography | DOF |Camera
Depth of Field - The Three Rules | Photography | DOF |Camera
::2008/01/20::
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48
Canon EF 50mm f/1.8 II - Focus Test / Depth of Field - Canon 60D - HD
Canon EF 50mm f/1.8 II - Focus Test / Depth of Field - Canon 60D - HD
::2013/01/09::
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49
Canon Vixia HF R20 test manual focus depth of field
Canon Vixia HF R20 test manual focus depth of field
::2012/05/11::
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50
Canon 550D/T2i & EF 50 f1.8 II, Razor Thin Depth Of Focus
Canon 550D/T2i & EF 50 f1.8 II, Razor Thin Depth Of Focus
::2011/03/13::
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From Wikipedia, the free encyclopedia
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For the seismology term, see Depth of focus (tectonics).

Depth of focus is a lens optics concept that measures the tolerance of placement of the image plane (the film plane in a camera) in relation to the lens. In a camera, depth of focus indicates the tolerance of the film's displacement within the camera, and is therefore sometimes referred to as "lens-to-film tolerance."

Depth of focus vs depth of field[edit]

While the phrase depth of focus was historically used, and is sometimes still used, to mean depth of field (DOF), in modern times it is more often reserved for the image-side depth.

Depth of field is the range of distances in object space for which object points are imaged with acceptable sharpness with a fixed position of the image plane (the plane of the film or electronic sensor). Depth of focus can have two slightly different meanings. The first is the distance over which the image plane can be displaced while a single object plane remains in acceptably sharp focus;[1][2] the second is the image-side conjugate of depth of field.[2] With the first meaning, the depth of focus is symmetrical about the image plane; with the second, the depth of focus is greater on the far side of the image plane, though in most cases the distances are approximately equal.

Where depth of field often can be measured in macroscopic units such as meters and feet, depth of focus is typically measured in microscopic units such as fractions of a millimeter or thousandths of an inch.

The same factors that determine depth of field also determine depth of focus, but these factors can have different effects than they have in depth of field. Both depth of field and depth of focus increase with smaller apertures. For distant subjects (beyond macro range), depth of focus is relatively insensitive to focal length and subject distance, for a fixed f-number. In the macro region, depth of focus increases with longer focal length or closer subject distance, while depth of field decreases.

Determining factors[edit]

In small-format cameras, the smaller circle of confusion limit yields a proportionately smaller depth of focus. In motion picture cameras, different lens mount and camera gate combinations have exact flange focal depth measurements to which lenses are calibrated.

The choice to place gels or other filters behind the lens becomes a much more critical decision when dealing with smaller formats. Placement of items behind the lens will alter the optics pathway, shifting the focal plane. Therefore, often this insertion must be done in concert with stopping down the lens in order to compensate enough to make any shift negligible given a greater depth of focus. It is often advised in 35 mm motion picture filmmaking not to use filters behind the lens if the lens is wider than 25 mm.

Calculation[edit]

If the depth of focus relates to a single plane in object space, it can be calculated from[1]

t = 2Nc \frac {v} {f} \,,

where t is the total depth of focus, N is the lens f-number, c is the circle of confusion, v is the image distance, and f is the lens focal length. In most cases, the image distance (not to be confused with subject distance) is not easily determined; the depth of focus can also be given in terms of magnification m:

t = 2Nc \left ( 1 + m \right ) \,.

The magnification depends on the focal length and the subject distance, and sometimes it can be difficult to estimate. When the magnification is small, the formula simplifies to

t \approx 2Nc \,.

The simple formula is often used as a guideline, as it is much easier to calculate, and in many cases, the difference from the exact formula is insignificant. Moreover, the simple formula will always err on the conservative side (i.e., depth of focus will always be greater than calculated).

Following historical convention, the circle of confusion is sometimes taken as the lens focal length divided by 1000 (with the result in same units as the focal length);[3][4] this formula makes most sense in the case of normal lens (as opposed to wide-angle or telephoto), where the focal length is a representation of the format size. This practice is now deprecated; it is more common to base the circle of confusion on the format size (for example, the diagonal divided by 1000 or 1500).[4]

In astronomy, the depth of focus \Delta f  is the amount of defocus that introduces a  \pm \lambda/4 wavefront error, and can be calculated using[5][6]

 \Delta f =  \pm 2 \lambda N^2 .

References[edit]

  1. ^ a b Larmore 1965, p. 167.
  2. ^ a b Ray 2000, p. 56.
  3. ^ Larmore 1965, p. 163.
  4. ^ a b Ray 2000, p. 53.
  5. ^ McLean 2008, p. 238.
  6. ^ Lipson, Lipson, and Lipson 2010.
  • Hart, Douglas C. 1996. The Camera Assistant: A Complete Professional Handbook. Newton, MA: Focal Press. ISBN 0-240-80042-7
  • Hummel, Rob (editor). 2001. American Cinematographer Manual, 8th edition. Hollywood: ASC Press. ISBN 0-935578-15-3
  • Larmore, Lewis. 1965. Introduction to Photographic Principles. 2nd ed. New York: Dover Publications, Inc.
  • Lipson, Stephen G., Ariel Lipson, and Henry Lipson. 2010. Optical Physics. 4th ed. Cambridge: Cambridge University Press. ISBN 978-0-521-49345-1 (scheduled release October 2010)
  • McLean, Ian S. (2008). Electronic Imaging in Astronomy: Detectors and Instrumentation (2nd ed.). Chichester, UK: Praxis Publishing Ltd. ISBN 3-540-76582-4. 
  • Ray, Sidney F. 2000. The geometry of image formation. In The Manual of Photography: Photographic and Digital Imaging, 9th ed. Ed. Ralph E. Jacobson, Sidney F. Ray, Geoffrey G. Atteridge, and Norman R. Axford. Oxford: Focal Press. ISBN 0-240-51574-9
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