Week 2 aperture, shutter speed and iso


Published on

1 Like
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide
  • We are always looking for reasons for not taking good pictures. Cartier-Bresson used film camera, same lens, no flash, same shutter speed – he didn’t need the newest digital equipment to take great photos. We all have access to some subjects that no one else has access to – look at your friends’ hobbies, the workplaces of friends and family, and any place you have access to to find a vision that comes uniquely from your access. Many people would dream of having the same access you have, and you might not have considered how valuable your access is.
  • Focus attention on the main subject (whatever your subject is, make sure it is evident by the composition) Rules of thirds: basis for well balanced and interesting shots The basic principle behind the rule of thirds is to imagine breaking an image down into thirds (both horizontally and vertically) so that you have 9 parts. With this grid in mind the ‘rule of thirds’ now identifies four important parts of the image that you should consider placing points of interest in as you frame your image. Studies have shown that if you place points of interest in the intersections or along the lines that your photo becomes more balanced and will enable a viewer of the image to interact with it more naturally.
  • Focus attention on the main subject (whatever your subject is, make sure it is evident by the composition)
  • Theme –universal message Wedding (concept of love & marriage) Nature (simplicity of a flower) Something everyone can relate to Focus attention on the main subject
  • Theme –universal message Wedding (concept of love & marriage) Nature (simplicity of a flower) Something everyone can relate to Focus attention on the main subject
  • Window Analogy
  • Each next f/stop (aperture) setting reduces the amount of light entering the camera by half. We can use the terms f/stop and aperture interchangeably as for our purposes they mean the same thing. The larger the number, the smaller the aperture, the smaller the number, the larger the aperture, and, the larger the aperture, the more light enters the camera. The aperture selector adjusts the size of the lens opening. F/4 lets in twice as much light as f/5.6 etc.. The lower the f-number, the larger the lens aperture.
  • Depth of Field: Lens opening (f-stop) The smaller the aperture, the greater the depth of field. Focus distance The greater the focus distance from camera to subject, the greater the depth of field. Focal length of lens The shorter the focal length, the greater depth of field.
  • It is also important to understand that focusing works according to the distance from the camera to the subject. You cannot focus on the left part of a scene and leave the right part blurry, but you can focus on something at a certain distance from the camera and leave everything else blurry. For example, you can focus on the foreground and leave the background blurry. The distance in front of and behind the focusing point, in which everything appears to be “acceptably sharp”, is referred to as the depth of field.
  • The shutter-speed selector controls the length of time that the shutter remains open. The shorter that time is, the less likely a moving object will appear blurred.
  • Your shutter speed should always be shorter than the reciprocal of twice your lens length.
  • Slower films are less sensitive and generally require longer exposures / more light. Faster films react rapidly, and can be used in low light situations. Film speed ratings double each time the sensitivity of the film doubles. An ISO 100 film is one stop slower than an ISO 200 film. It needs twice as much light as the ISO 200 film for correct exposure. The more sensitive the film, the more “grainy” it is.
  • Film speed (or ISO) is a measurement of how sensitive your camera's sensor (or in the case of a film camera, your camera's film) is to light. The larger the ISO (higher number), the more sensitive it is to light. The smaller the ISO (smaller number), the less sensitive it is to light. Each step up in ISO doubles the amount of light sensitivity (ISO 400 is 2x as sensitive to light as ISO 200). Using a higher ISO, you can sometimes get shots in low light that would have required a longer shutter speed or a larger aperture if you were using a lower ISO. However, this does not come without its setbacks. The higher the ISO is set, the grainier your picture will appear. At higher ISOs, you will notice some extremely substantial grain. ISO noise is much less noticable in DSLR and other large sensor cameras than it is in point and shoot cameras.
  • Large apertures (small f/ratio numbers) are subject to lens unsharpness. Some lenses are worse than others at full aperture, but as a rule you should use a lens at apertures of 2 or 3 stops smaller than wide open, if the available light permits. Aperture determines the depth of focus . With landscape photography this is usually not an issue since most subjects are at infinity, so the depth of focus is irrelevant. But for macro photography, for example, it is very important. Long exposure times require a tripod , and will usually blur the photo if you photograph moving subjects. With film, long exposure times will also suffer from reciprocity errors. Short exposure times however are not always possible because the light may be too low. Low film sensitivities (low ISO number) require longer exposures, which is not always possible, and high film sensitivities suffer from coarse film grain (or, with digital sensors, from thermal noise).
  • Now that we see how exposure is controlled by aperture, shutter and film speed, now we need to know how to control it. Fortunately, with DSLRs, they have what is called pre-sets. These are preset/calculated/programed setting for different situations a photographer my encounter. These settings are commonly located on the control dial.
  • Basic Zone (Pre-Sets) Portrait Mode – icon- a head in profile. Use this mode when you want a subject in the foreground in sharp focus. Landscape Mode - Icon = mountains. Use this mode when you want a wide-angle shot with the background in focus. Night Scene (portrait) Mode - Icon = starry field. Use this mode when you're shooting a subject at night. Illuminates the subject with the flash, while keeping the shutter open longer to provide more light for the background. Creates a balance. Black and White Mode - Icon = a figure in contrast. Use this mode to take pictures in black and white Macro (close up ) Mode - Icon = a flower. Use this mode for extreme close-ups. Blurs the background, narrow DPF. Sports Mode - Icon = a running figure. For shooting scenes with lots of motion, which you want to capture without blurring .
  • All the focus squares are used to find the nearest and farthest objects in your viewfinder. The camera then calculates the best setting to give you the ideal depth of field.
  • ×