DVD 2: A perture and Depth of Field

1. DVD 2:Aperture and Depth of Field

2. Exposure • The amount of light that is allowed to hit the imaging chip in a digital camera

3. Exposure is the single most important factor in image quality

4. 3 Things Control Exposure • Aperture/ F-stop • Shutter speed • Film Speed

5. Controlling Exposure:Aperture & Shutter Speeds • Each control the amount of light that reaches an electronic sensor of your camera. • F-stop (Aperture):size of the lens opening • Shutter speed:amount of time that light is allowed to pass through the opening.

6. Aperture (F-stops) • The lens opening that allows light to enter the camera. • Aperture is denoted by f-stop fractions.

7. Aperture Aperture refers to the diaphragm or lens openingand controls the amount of light allowed onto the sensor. If a scene has a lot of light then the aperture can be smaller.If the scene has low light then the aperture can be fully openedto allow as much light as possible. Aperture also influences the depth of field.

8. Aperture, F-Number • Aperture : Diameter D of the lens that is exposed to light. • F-Number(f/#): • For example, if f is 16 times the pupil diameter, then f/#=f/16. • The greater the f/#, the less light per unit area reaches the image plane. • f-stops represent a convenient sequence of f/# in a geometric progression.

9. Aperture & F-stops • The F-number indicates how many times the diameter of the lens opening can be divided into the focal length . • Smaller f-numbers = larger apertures. • Higher f-numbers = smaller apertures. • A higher F-number (smaller aperture) will increase the depth of field.

10. F-stops • The f-number is often referred to as the f-stop. • “Stops” quantify light/exposure ratios. • Each stop change allows exactly half or double the amount of light.

11. F-stops • one stop difference between each whole f-stop number. • Smaller numbers = more light. Bigger numbers = less. • f/8 doubles the light of f/11 • f/16 half the light of f/11

12. Reciprocity • Decrease the amount of light by changing to a smalleraperture -- you must --- • Increasethe amount of light by changing to a slowershutter speed.

13. Depth of Field • Depth of field it's one of the most important tools any photographer has because it allows you to control the amount of sharpness that appears in your finished picture.

14. Depth of Field • Refers to how much of the scene is in focus both in front of and behind the subject or the point of focus.

15. Depth of field zone • one thirdin front of the focus point and two thirdsbehind the focus point. • If the depth of field zone is enlarged or reduced the relation of 1/3 and 2/3 remains unchanged. • Any scene that stretches away from the camera should be photographed by focusing on the end of the first thirdof the scene. Figures 2 and 4 fall are inside the zone & will be in focus Figures 1 and 5 fall outside the zone & will be out of focus

16. Factors the influenceDepth of Field • Aperture (diaphragm or lens opening) • Focal length of the lens • Distance between the lens and the focus point

17. F-stop & Depth of field • The smaller /larger(circle one)the diaphragm the more depth of field. • This also means the smaller /larger(circle one)f-STOPnumber

18. Setting the Aperture Depth-of-Field Short Long Low F-stop 3.2 High F-stop 16

19. Depth of Field Both near and farther scene areas are blurred

20. Focal length

21. Focal length & Depth of field • The shorter/longer (circle one)the focal length of the lens used the more the depth of field

22. Depth of field & lenses • Wide angle lensdeeper/limited depth of field. (circle one) • Telephoto lensesdeeper/limited depth of field. (circle one)

23. Distance & Depth of field The shorter the distance between lens and subject the smaller the depth of field

24. Depth of field & Image Sensors • The image sensors used in digital cameras come in all different sizes. While small size sensors may give you poorer image quality, they also give you an decreased/increased depth of field • All digital sensors are smaller than 35mm film , therefore, you inherently get more/less(circle one)depth of field with digital cameras then you do with standard 35mm cameras.

25. Tips: Portrait • Increase/decrease(circle one)the depth of field (lower f-stop value) so that the background "blurs" and does not distract from the main subject.

26. Tips: Landscape • To get more depth of field use a higher/lower (circle one)f-stop value.

27. Aperture priority • Most digital cameras have this shooting mode. • Set the f-stop you want to use and the camera automatically sets the shutter speed to compensate for your exposure. • When using this mode, the _point of initial focus_ is key. (again, keep in mind the idea of depth of field) • If you are shooting landscapes and want to large depth of field, you set your camera to Aperture Priority and select f/11now all your pictures will be taken at that aperture. • If you are shooting close-ups of flowers and want a shallow depth of field you would set your camera to Aperture Priority and set your f-stop at f/4, now all you images would be taken at that f-stop with the camera automatically setting the corresponding shutter speed.

28. Questions • _Focus___ is the way you make subjects sharp in a photo. • The term that describes the range in space from near to far that seems sharp or in focus in the photo is the _depth of field_. • The aperture_ setting is the diameter of the opening of the lens. • The higher numbers represent_ smaller_ openings.Each aperture number is referred to as a ___stop___ • What is the value in controlling the depth of field in your photographs? • Allows for isolating a subject in and out of focusBackground as a creative tool…

29. How it works • Describe the difference between in focus and out of focus in terms of light hitting the camera sensor. Answer this in terms of LIGHT RAYS. • In focus:converges right on the surface of the sensor • Out of focus: converges before or beyond the sensor. • How does the circle of confusion aperture opening interact to give a sense of a greater or lesser depth of field? • to cone of light created by divergent light raysfrom different distances before or afterthe sensor surface small diameter is sharp while one larger than circle of confusion is not sharp

30. How it works • What is depth of field?distance in focus • How does Aperture affect depth of field?lets in more or less light making the circle of confusion larger or smaller… • How does focal length affect depth of field?The shorter the focal length the more depth of field • How does the camera’s distance to the subject affect depth of field?The shorter the distance the smaller the depth of field