Lenses Contain both convex and concave lenses. Lenses Many concave and convex lenses, called elements are grouped together to produce a specific magnification

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Text of Lenses Contain both convex and concave lenses. Lenses Many concave and convex lenses, called...

  • LensesContain both convex and concave lenses

  • LensesMany concave and convex lenses, called elements are grouped together to produce a specific magnification and correct color aberrations

  • LensesEach element adds the chance for reflection in the lensCalled lens flare

  • Focal LengthA measurement of the magnifying power of a lens

  • Focal LengthAs magnification increases, field of view decreases50mm - normal film lens

  • Prime and Zoom LensesPrime Lens - fixed focal lengthZoom - can adjust the focal length (magnification)

  • Focal Length - Normal Lens

  • Focal Length - Normal Lens

  • ExposureImage sensor needs only a tiny bit of light to expose an image

  • ExposureToo much light, the picture is overexposedToo little light, the picture is underexposed

  • ExposureA camera has two mechanical mechanisms for controlling exposure:Aperture ShutterShutter, Aperture (in the lens)

  • Exposure - ApertureAn expandable opening like the iris of your eye that controls how much light passes through the lens

  • Exposure - ApertureUsually constructed of thin, sliding, interlocking metal plates

  • Exposure - ApertureAs you close the iris down to a smaller aperture, it stops more light from reaching the image sensor

  • Exposure - ApertureThe size of the aperture is measured in stops or f-stopsThe higher the f-stop rating, the more light the aperture is stopping

  • Exposure - ApertureLens speed is determined by how wide its iris or aperture can open.The wider the aperture, the faster the exposure can be.

  • Exposure - Fast lensesA lens that can be opened to f1.8 is much faster than a lens that can only open to f4.Can shoot in lower light and have a wider range of aperture settings - more creative freedom.More difficult to build - more expensive

  • Exposure - ApertureAperture and shutter speed are interrelated

  • Exposure - ShutterOpens and closes very quickly to control how much light passes through to the image sensor

  • Exposure - ShutterShutter speed is a measure of how long the shutter stays open, measured in seconds and fractions of seconds

  • Exposure - ReciprocityMeans that many different shutter speed/aperture settings all yield the same exposure1/30 @ f161/60 @ f111/125 @ f8

  • Exposure - ReciprocityIf shutter speed or aperture is shifted in one direction, the other is shifted in the opposite direction the same amount.

  • Exposure - ReciprocityIf a proper exposure calls for 1/60 sec. and f16, what should the f-stop be if the exposure time was decreased to 1/125?

  • Exposure - ReciprocityISO can also affect shutter speed and/or aperture settings

  • Exposure - ReciprocityEvery time the ISO value is doubled, it makes the image sensor twice as sensitiveEach value = 1 stop

  • Exposure - ReciprocityThe higher the ISO value, the more noise there is in the picture, similar to grain in an image made from film with a higher ISO.

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