Controlling Your Depth of Field

1. What are the different factors that you can use to control depth of field that this video mentions? What is one of the primary ways to control depth of field?

The aperture, the distance between the subject and the lens, and the focal length of the lens all play a role in changing the depth of field. The most accessible way to alter the depth of field is to change the aperture. Once the desired depth of field is adjusted using the aperture, other setting must be adjusted accordingly. This includes the light level, ND filters, ISO, and the shutter speed. Changing the focal length of your length can also alter the depth of field. For prime lenses, this can only be done by switching out lenses. However for zoom lenses, there is the option to change the focal length by zooming in. It is important to regard that in a zoomed in shot, space will appear compressed. If a subject is closer to the lens, a shallower depth of field can be accomplished. This may be difficult because the composition of the shot must be manipulated in order to create this look.

Depth of Field P.3

1. What is crop factor?
2. What is lens equivalency?
3. If you had a full frame sensor and your cousin had a APS-C sized sensor, how would you explain the differences between the camera's and lenses to your cousin?

Crop factor is defined by the amount zoomed in depending on the size of the sensor. For example, a smaller sensor will create a greater a crop factor, resulting in a more zoomed in image. In a standard 35mm camera, many photographers and videographers understand what a different focal length lenses look like. However, keeping the sensor size into consideration, lens equivalency can be calculated by multiplying the crop factor and the focal length. An APS-C sensor with a crop factor of 1.6, a 50mm focal length would be the equivalent to a 80mm on a 35mm aka full frame sensor. When you attempt to match the focal length to compensate for the crop factor, the bokeh in the background changes. This is because the crop factor is not only multiplied to the focal length, but it is also multiplied by the F-stop number. when the F-stop is adjusted to create a similar bokeh in the background, the ISO must be multiplied by the crop factor^2 as well. As a result, smaller sensors shoot the equivalent of a higher focal length and aperture, resulting in a deeper depth of field.

Depth of Field P.2

Answer the following questions in an in depth - paragraph:

1. What is the circle of confusion?
2. How does this affect what the viewer of the image perceives overall?
3. How does the camera's sensor come into play with the circle of confusion? Why?

The circle of confusion is defined by the size of the spot of light that is acceptable to be considered "sharp enough." This is a subjective matter that its accuracy is generally determined by the size of the print or screen that the content is going to be viewed in. In general terms, the bigger the projected screen, the smaller the "acceptable spot of light" becomes. The circle of confusion is altered when speaking in terms of digital mediums. Because digital mediums are captured in pixels, the circle of confusion is defined by the size of the pixel. The smaller the pixel sizes, the more accurate the focus has to be in order to be considered in focus. Thus, as a result, the higher the resolution, the shallower the depth of field. In other words. A smaller sensor will inevitably create a shallower depth of field.

Depth of Field P.1

Answer the following questions in an in depth - paragraph:

1. In your own words, explain what depth of field is.
2. What is deep depth of field? What is shallow depth of field? What might you use it for in a video?

 Depth of field is determined by the amount of space that a certain subject is "acceptably" in focus. For example, if a subject goes easily out of focus just by moving it slightly towards or away from the camera, it has a shallow depth of field. If a subject stays in focus even when the subject is moved visibly and drastically, it has a deep depth of field. The length of the depth of field can be calculated by seeing how far back the lens can go without going out of focus in both directions. Depth of field can also be determined by the aperture. For example, a smaller aperture can make an image that creates a wider range of acceptable depth of field.

Lenses P.3

Answer the following questions in an in depth - paragraph:

1. What are the key difference between photography and cine lens?
2. What are the key differences between prime and zoom lenses? What are the drawbacks and benefits of each?

The main difference between a cine lens and a photography lens lies in the Focus Breathing. Photography lenses, holding a single focal length, can zoom in or out as a result of focusing an image. This aspect of the lens is not an issue when it comes to photography. However, it may pose an issue when it comes to filmmaking. This is where the cine lens comes into play. Cine lenses are able to eliminate focus breathing. Prime lenses are often cheaper and better quality in comparison to their zoom counterparts. On the other hand, zoom lenses are capable of shooting a range of multiple focal points. Zoom lenses can be separated into two groups: Varifocal and Parfocal lenses. A Varifocal lens causes the focus to change as the focal length changes, while a Parfocal lens will maintain the focus independent from the focal length. While prime lenses may sacrifice some quality, it allows the filmmaker to have more flexibility while shooting. Another drawback worth mentioning is that the aperture may not be available for all focal lengths. This is especially the case when it comes to the lens's maximum focal lengths.

Filmmaker IQ Lenses P.2

Answer the following questions in an in depth - paragraph:

1. How does the diameter of the aperture affect the focus of the image?
2.What is an F-stop? How are they calculated?
3. What is a T-stop? How is it different from an F-stop?

A smaller aperture results in a sharper image by restricting the angle of light traveling through the system. However, this can cause less light to be exposed onto the sensor, which can be problematic in a darker situation. The F-number, or the F-stop, can be calculated by dividing the focal length by the diameter of the aperture. In order to double the amount of light that hits the sensor, the diameter must be increased by dividing the Fstop by 1.4. It is important to note that the different amount of light may hit the screen even wit the the same F stop value depending on the structure of the camera. In this case, cinematographers will use a scale known as the T-stop. T-stops are numbers that are corrected according to the F-stops numbers. This way, the same T-stops will have the same exposure levels even on lenses with different focal lengths.

Lenses P.1

Answer the following questions in two in depth - paragraphs:

1. What is crop factor? How does it affect the image shot with different lenses?
2. What is a "normal" lens? What is a wide angle lens? What is a telephoto lens? How do they affect the image that is shot?

Crop factor refers to the "magnitude of the crop as compared to a 35mm still horizontal standard." Different size sensors can cause the image to capture a smaller cropped image in comparison to a full frame shot. This field of view that is available to be seen through the camera is also determined by the focal length of the lens. A "normal" lens refers to lenses with  focal length that replicates how humans normally see with their eyes. What is considered to be a "normal" lens depends on the way it is displayed and the sensor size. For example, if the footage is intended for the big screen, the diagonal line's length is twice the average camera. For full frame average cameras for normal screens, 43mm will create a "normal" view, while a smaller sensor size will require diagonals ranging from 26mm to 22.5mm if on a micro 4/3rds camera. Other lenses include telephoto lenses which zooms in as a result of a higher crop factor and wide-angle lenses which captures a larger field of view