Digital Photography

download Digital Photography

of 25

  • date post

    22-Jan-2016
  • Category

    Documents

  • view

    26
  • download

    0

Embed Size (px)

description

Digital Photography. Part 3 Creative control. What are creative controls?. The key factors that decide how a composition will look: focusing white balance shutter speed aperture focal length - PowerPoint PPT Presentation

Transcript of Digital Photography

  • Digital PhotographyPart 3Creative control

    Pter Tarjn

  • What are creative controls?The key factors that decide how a composition will look:focusingwhite balanceshutter speed aperturefocal lengthCameras can set these automatically (except focal length), but learning how to use them manually helps in getting great pictures.

    Pter Tarjn

  • Shutter speedShutter speed is one of the 2 factors that determine exposure. Shutter speed is the time interval during which the shutter is open and the sensor is getting light. For every full stop, the amount of light on the sensor is (about) doubled/halved.Reasons to set shutter speed manually:avoid camera shakefreeze movementblur movementpanningincrease/reduce depth of fieldThe standard shutter speeds:

    Pter Tarjn

  • Effect of shutter speed

    Pter Tarjn

  • Steady shootingWhen shutter speed is low, camera shake may blur the image. Its effect can be greatly reduced by holding the camera correctly.Hold the camera firmly with both hands. Stand with your feet slightly apart. Hold your elbows close to your body. Squeeze the shutter button gently. Get additional support from knees, walls, ledgesExperiment what works for you. More good tips here:http://knol.google.com/k/vesna-kozelj/how-to-hold-the-camera-with-your-hands/3k0expg5xjecw/2#

    Pter Tarjn

  • Freezing movementFor freezing movement, you need a fast shutter speed. But how fast? It depends on how fast the subject is moving across the frame not the actual speed! Distance to the subject also counts. Subjects moving towards or away from the camera need slower shutter speed than those moving across the frame. Also: for close subjects, you can use a flash it almost always freezes the movement.

    Pter Tarjn

  • Effect of freezing movement

    Pter Tarjn

  • Blurred movementFast shutter speeds sometimes fail to convey the dynamism of a moving subject: a speeding car may look just like a parked one. Choosing a slow shutter speed blurs the movement, which may work better. Shutter speed shouldnt be just slighly slow (blur without the artistic effect) or too slow (image may be unrecognizable). Rule of thumb: 4 stops slower shutter than what you would use for freezing the action.Panning: tracking a subject with the camera, using slow shutter speed, causing the subject to remain sharp and background to blur. Technique: hold the camera steady with two hands swing your shoulders from your waist, without moving your feet leave more space in front of the moving subject than behind follow the subject across and press the shutter button smoothly take lots of shots to get a few that work

    Pter Tarjn

  • Blurring

    Pter Tarjn

  • Extended exposuresIn low light, exposures of more than 1 second may be needed. Some tips:Support the camera.If the camera is supported, you are free to choose any shutter speed. Choose shutter speed/aperture to suit your needs.Choose the lowest ISO setting to minimize noise.Use self-timer/shutter release cable/remote control to fire the camera.Avoid the widest aperture settings to maximize image quality. If you cant get a slow enough shutter speed, use a neutral density filter. Low-light shots tend to be overexposed by the camera; correct for that or use manual exposure.Camera supports whatever you find beanbag unipod (monopod) tripod (pan-tilt head, ball-and-socket head)telescopic legscenter columnhandlehead (with camera platform and quick-release shoe)crank

    Pter Tarjn

  • Effect of extended exposures

    Pter Tarjn

  • Depth of fieldIn principle only objects at a given distance from the lens are sharp everything closer or further away are blurred to varying degrees. The blur is invisible for a given range of distances around the focusing distance, so everything within that range looks sharp. This range is called the Depth of Field (DoF). Depth of Field depends on a number of factors.Factors determining DoF: aperture: the smaller the aperture (higher f-stops), the more the DoF. focusing distance (subject distance): the farther away the focus is, the more the DoF. focal length (zoom setting): the shorter the focal length (=wide angle) the more the DoF. circle of confusion: how big a circle you are willing accept as point. Subjective! It also depends on image magnification and how closely it is viewed.

    Pter Tarjn

  • Depth of field: aperture effect7.4 mm focal length (35 mm efl), focus on red die

    Pter Tarjn

  • Depth of field: focal length effectfocus on red die, f/4.0

    Pter Tarjn

  • Depth of field: focusing distance effectefl 65 mm, f/3.2

    Pter Tarjn

  • Depth of field: size mattersIs the yellow die sharp? It depends on the magnification and yourdefinition of sharp.

    Pter Tarjn

  • Maximizing depthUse the controls together to maximize DoF: use wide lens/zoom setting, close the aperture, get further away from the foreground elements. Multipoint autofocus helps. The through-the-lens (TTL) viewfinder of bridge and SLR cameras may give an idea of DoF.

    Pter Tarjn

  • Minimizing depthThrowing things out of focus is usually much more difficult on digital cameras SLRs rule here. The main things you can do:use long telephotouse wide apertureget close to subjectWhy? Keeping parts of the picture blurred can help concentrate on the main subject and can result in more powerful pictures.

    Pter Tarjn

  • More DoF tipsDoF in close-up photography isextremely narrow fight it or use it to your advantagefocusDoF
  • Aperture and lens resolutionIn several picture-taking situation, more than one shutter speed-aperture combination yields a shake-free picture and enough DoF. In that case, you can take one other factor into consideration: lens resolution.Lenses provide their best resolution at their mid-apertures. Wider settings decrease resolvable detail because lenses work better optically near their center than their edges. At small apertures, diffraction on the edges of the aperture itself causes another drop in image quality. Quality decrease due to diffraction is worse for smaller sensors. Thus, SLRs can use narrower apertures (typically f/22) before diffraction becomes significant than zoom compacts (typically f/8) or bridge cameras (f/11).Bottom line: use a mid-aperture setting whenever you can.

    Pter Tarjn

  • Focal lengthChanging the focal length of the lens by zooming changes the angle of view of the camera. This is a very important compositional tool:useful for cropping when taking the pictureallows you to maximize sensor effectivenesschanging it together with the subject distance, it gives more flexibility in choosing backgroundallows you to take very different types of shots.

    Pter Tarjn

  • PerspectivePerspective is the optical effect that makes distant objects appear smaller than close ones and parallel lines seem to converge. It gives vital clues about depth in the picture. Perspective depends only on the distance! But using different focal lengths can change the picture because telephoto lenses are used from further away and that changes perspective.same perspective!different perspective

    Pter Tarjn

  • Manipulating the backgroundWhether using wide-angle or telephoto lenses, you can end up with very similar-looking pictures. What can change dramatically when you change focal length (and subject distance) is what is in the background and how it looks (DoF, perspective).

    Pter Tarjn

  • Wide-angle lensesWide-angle lenses offer a wider field of view than our eyes. Uses:fit a lot of things into the frameexaggerate foreground create a wide DoFProblem: barrel distortion

    Pter Tarjn

  • Telephoto lensesTelephoto lenses offer a narrower field of view than our eyes. Uses:bring distant objects closercompress distances between objectscreate a narrow DoFProblem: heavy, magnifies camera shake

    Pter Tarjn

    camera shake with mirroralways a compromisehow to choose shutter speed, aperturetripods for still lifetripod head typesND filters!why would you want to do that?animals, cage