Depth of Field Treasure Valley Club Allen Baxter December 19, 2018 • Objective: • Introduce the topic • Review some basic principles • Provide links to some other resources • Explore how you can use in your Depth of Field – Definition • Definition • Depth of field is the distance between the closest and farthest objects in a photo that appears “acceptably sharp”. • Acceptably Sharp is a loose term and depends on: • How you will be viewing the image • What size the image is • Vision

• Circle of Confusion Depth of Field - Illustration Factors Affecting Depth of Field

• Three factors: • • Distance to subject •

• Group 1: • Aperture • Diameter of • Magnification • Distance to Subject • Focal Length

• Group 2: • Distance to subject • Diameter of Entrance pupil • Aperture • Focal length Affect on Depth of Field

• Aperture is the opening in the : • Large number means smaller opening • Greater depth of field • Small number means large opening • Less depth of field Camera To Subject Distance Affect on Depth of Field • Closer subject is to camera the less depth of field • Marco photography

• The further subject is from the camera the more depth of field • Focal Length of Lens

• Typical rational says: • Telephoto – less depth of field • Normal • Wide Angle – more depth of field • Only applies if we do not change our camera-subject distance. • Field of view is drastically different hence comparison is difficult. • We can actually produce the same depth of field if we compare similar fields of view. • The apparent difference has to do with magnification/compression of the background Focal Length – Field of View Sensor Size Affect on Depth of Field

• We often hear that with a smaller sensor have a greater depth of field. • Only true if we are comparing equivalent focal length lens • For example equivalent lens focal length: 1.0 Crop Factor – Full Frame 35mm 1.5 Crop Factor – APS C 23mm 2.0 Crop Factor – Micro 4/3 17mm • Can you capture image with different format that has the same depth of field? Yes • Need to change the Aperture and/or focal length Entrance Pupil and the Relationship between Aperture, Focal Length •Formula: • N=f/D • N = Aperture • F = focal length • D = diameter of entrance pupil Entrance Pupil and Affect on Depth of Field • Sample calculations Entrance Pupil (EP)Relationship to Depth of Field • The larger the #: • Rays of light converge more narrowly and hence produce a narrow/shallow depth of field. • The smaller the #: • Rays of light converge more sharply and hence produce a deep/wide depth of field. • We can change the EP by changing the: • Focal length • aperture (f stop) Entrance Pupil Illustration

Larger # Sharper Angle of light rays and hence smaller

Smaller # Wider Angle of light rays and hence wider Depth of Field – Defined by CoC DOF Examples of Depth of Field (DOF)

• Best App for simulating DOF for various: • Lens focal lengths • Aperture • Distances • Sensor sizes

• Depth of Field Simulator • https://dofsimulator.net/en/ How can we use Depth of Field

• Portraits • Those things in focus draw our attention • A portrait with the main image in sharp focus and the background blurred places the focus on the person. • The eyes in focus and the remainder in softer focus. • Typically is going to require a large aperture or small f stop: f1.2, f2.0

How can we use Depth of Field

• Landscape and Macro • Everything in focus from front to back requires large depth of field or wide range of focus • Small aperture or large f stop: f11, f16, f22 • Focus stacking

How can we use Depth of Field

• Hybrid – giga pano portraits • Technique made popular by wedding photographer Ryan Brenizer • Combines: • Longer focal length lens: 50mm or greater. • Wide open aperture of lens. • Multiple shot to create the panorama.

Apps for calculating DOF

• There are many apps • Problem with many of them is they do not necessarily take into consideration the Circle of Confusion or at least let you adjust it. • They do not take into consideration the effect of . • Diffraction increases as you increase the fstop • Contributes to blurry images

• My preferred app: • http://www.georgedouvos.com/douvos/George_Douvos__Innovative_ Apps_for_Photographers_and_Cinematographers.html