UNDERSTANDING THE EXPOSURE TRIANGLE. By Ken Haubrich

Transcription

1 UNDERSTANDING THE EXPOSURE TRIANGLE By Ken Haubrich

2 FUNCTIONING PARTS OF THE CAMERA

3 What happens when we push the shutter button ½ way down The Camera: In at least one of the automation modes 1 ST FOCUS ON THE SUBJECT 2 ND EVALUATES THE AMBIENT LIGHT 3 RD SETS APERTURE, SHUTTER SPEED AND ISO IN THIS CLASS WE WILL LEARN TO CONTROL ALL OF THESE VARIABLES BY SETTING THE CAMERA TO MANUAL. THIS WILL GIVE US AN OPPORTUNATY TO UNDERSTAND WHAT EACH OF THESE HAS ON THE IMAGE.

4 WHAT ARE THE COMPONENTS OF EXPOSURE TRIANGLE The Exposure triangle is a representation of the relationship between the three main elements of photography ISO- Sensitivity of the camera s sensor Aperture - the opening of the iris in the lens ( f stop) Shutter speed, or exposure time the length of time when the sensor is exposed to light.

5 Typical representation of the exposure triangle. Aperture ISO Shutter speed What changes all of this????? The amount of Light coming through the lens or..

6 you want to change the effect or appearance of the image. - Depth of field---- what is in focus---f-stop - Shutter speed--- to stop action - F-stop - to compensate for the ambient or artificial (or both) light coming to the sensor - ISO to work with very low ambient light

7 Lets breakdown the parts of the Exposure triangle.

8 ISO

9 To understand ISO one must master the following formulas and standards Scheiner {\sqrt[ {19}]{100}}^{3}= \approx 2 DIN- Deutsches Institut für Normung \log _{{10}}{(2)}= \approx 3/10 ASA American Standards Association ASA PH Standard ISO- International Organization for Standardization ISO 5800:2001

10 Actually better explained with the chart below

11 ONLY KIDDING

12 ISO- International Organization for Standardization ISO is: how sensitive the sensor in the camera is to light. It is represented in an ISO number

13 Examples of Noise - when the sensor is pushed beyond it s ability to produce a usable image

14 f-stop Focal Ratio

15 Looking down the lens when the Iris closes to a prescribed setting The Iris in the lens sets just before the image is taken

16 Iris settings are referred to as f stops. f1.0, f1.2, f1.4, f1.8.f64, f128 F 1.2 F 22

17 SHUTTER SPEED OR EXPOSURE TIME ACTUALLY IN DSLRS EXPOSURE TIME IS MORE CORRECT

18 Side X-ray view of SLR camera Be very careful taking pictures of Bunnies. Ex. Monty Python and the Holly Grail

19 DSLR SHUTTER VIEW TYPICAL SHUTTER SPEEDS RANGE FROM 30 SECONDS TO 1/8000 OF A SECOND MIRROR IN UP POSITION BEHIND THE SHUTTER IS THE SENSOR SHUTTER (ACTUALLY 2 CURTAINS) LENS CONTACTS

20 Now that we understand the parts let s see how they effect each other: -ISO -APERTURE -SHUTTER SPEED

21 Typical representation of the exposure triangle. Aperture Shutter speed ISO In this case an equilateral triangle What changes all of this: The amount of Light Or things we want to emphasize

22 Lets say the first equilateral triangle is perfect exposure as set by the camera in auto. BUT not everything is in focus the way you want it so you close the aperture to F-16 to increase the depth of field. This causes the shutter speed to decrease (75 th of second) to compensate. Likewise you wish to decrease depth of field to highlight one area you open the f stop to F-4. This causes the shutter speed to be increased to 175 th of a second F-8 F-16 F-4 Shutter speed Shutter speed Shutter speed 125 th 100 ISO As set by camera 75 th 100 ISO Long depth of field 175 th 100 ISO Short depth of field

23 Why would you want to change any of these variables? Areas effected by each of the parts of the triangle; - f-stop- What is in focus ( called depth of field) - Shutter speed- capturing the image in relation to speed - ISO- Quality of the image - Camera s choice of settings is wrong And these are just a few

24 The next few slides show are examples of why you would want to override the settings the camera s settings

25 EXAMPLE OF SHALLOW DEPTH OF FIELD

26 EXAMPLE OF STOP ACTION

27 EXAMPLE OF EFFECTS ISO HAS ON THE IMAGE

28 Let s experiment

29 Questions

30 In conclusion: When I started ( before rocks became dirt) all settings on the camera were manual, shutter, aperture, focus. ISO, which was called ASA, was determined by the film speed and you had to work to it. Film, and developing was expensive and you had to wait for that to come back from the lab, which seemed like eternity, or you shot black & white, because color in a home lab was hit or miss. So you limited the amount of shots taken. Ten rolls at a wedding, 360 photos, was typical. What I m trying to say is get off auto. Once you buy the camera the expense is minimal Experiment. Don t wait for family shoots where you are pressed to capture that moment. Purposely go out and take pictures, LOTS OF THEM and use the different setting. It will amaze you.