1. Lenses Lenses define 2 important things: Angle of view (focal length) Aperture

3. Film/Sensor Where the light is recorded Lens Bends the light Trajectory of light Subject Source of light Focusing A look at the overall camera system

4. Light converges at sensor Light converges past sensor Light converges before sensor Result: ‘In focus’‘Out of focus’

5. Result: ‘In focus’ Circle of confusion Image doesn’t have to perfectly converge. If it converges within a “circle of confusion”, it is still ‘in focus’ ‘In focus’ ‘Out of focus’

6. In focus Out of focus

7. Things at a certain distance are “in focus” (perfectly sharp) The further from this distance, the blurrier things are There is a range of distance where things are ‘sharp enough’ to be considered ‘in focus’. This range is known as the “depth of field” Amount of Blur Depth of field

8. Range that is ‘in focus’ Focus point Near limit of focus Far limit of focus Film/Sensor Where the light is recorded Circle of confusion Maximum non-convergance allowed to be ‘in focus’

9. Depth of field Circle of confusion When using a bigger lens (larger aperture), the depth of field shrinks

10. Depth of field Circle of confusion Longer subject distances mean larger depth of field range

11. Circle of confusion Longer focal lengths mean smaller depth of field range Depth of field

12. A = aperture f-number (e.g. f5.6) f = focal length (e.g. 50mm) d = distance to subject (e.g. 3000mm) c = circle of confusion (e.g..02mm) Factors to note: Smaller apertures (larger f-number) gives larger depth of field Shorter focal length gives larger depth of field Longer distance to subject gives larger depth of field Larger circle of confusion gives larger depth of field

13. As aperture increases, depth of field increases

14. As focal length increases, depth of field decreases. At very wide focal lengths (ultrawide), depth of field increases rapidly

15. Translating focal length into angle of view Angle of viewFocal length - 35mmFocal length - 1.5x APS-CFocal length – 1/1.7” 62.01°36mm24mm8mm Actual focal length35mm equivalent focal length

17. As subject distance increases, depth of field increases At very long subject distances, depth of field increases rapidly (hyperfocal distance)

18. For a constant magnification, depth of field is roughly the same across all distance/focal length combinations

19. Landscape/scenery Bokeh 40mm, f/2.8 280mm, f/2.8

20. Uses of large depth of field Landscape/scenery Architecture Small depth of field Macro

21. Uses of small depth of fieldPortraitsFlowers Sports Isolation

22. Focal length ranges Two types of lenses: Zooms (variable focal length) and Primes (fixed focal length) Different focal lengths are useful for different things Large aperture zooms As large as f/2.8 aperture Expensive! Canon 17-55 f2.8 $999 Canon 70-200 f2.8 $1139

23. Focal length ranges Two types of lenses: Zooms (variable focal length) and Primes (fixed focal length) Different focal lengths are useful for different things Large aperture primes Very large apertures (f2, f1.8, f1.4, f1.2) (Mostly) Cheaper than large aperture zooms Fixed focal length (angle of view) Nikon 85mm f1.8 $419 Canon 50mm f1.4 $316 Canon 50mm f1.8 $83

24. Portrait Assignment Focus on the following elements: Lighting (direction, intensity) Vantage point (camera direction, setting, background) Perspective (subject distance vs. focal length) Depth of field Directing the subject (poses, props, expression) Before shooting: Login to the gallery, choose 2 photos and evaluate each of these elements What was done, how it worked out, and how you would do it