VIDEO, SOUND, & MUSIC PRODUCTION
A CENTRAL MONTCO TECHNICAL HIGH SCHOOL PROGRAM
SECTION 10 LECTURES
Nikon D7500 Camera Setup
Nikon D7500 Comprehensive Guide
SIDE 1: APERTURE
Aperture is a measure of how open or closed the lens’ iris is. A wider aperture (or lower f-number) means more light will be let in by the lens, simply because the opening is larger. A narrower aperture (or higher f-number) allows less light to reach the sensor.
You might wonder why we would ever want less light to reach the sensor. The answer the majority of the time is that we want a larger depth of field. Depth of field is a byproduct of aperture. Narrower apertures (higher f-numbers) give a greater depth of field, allowing more of a scene to be in focus (think landscapes). Wider apertures (lower f-numbers) create a narrow depth of field, which can help isolate a subject and is one of the greatest compositional tools at your disposal (think portraiture).
You should also note that most lenses are their sharpest around f/5.6 or f/8. However, many photographers are willing to trade some sharpness for the subject-isolating effects of a wider aperture.
SIDE 2: SHUTTER SPEED
Shutter speed is a measure of how long the shutter remains open and thus, how long the sensor is exposed to light. Faster shutter speeds give the sensorless time to collect light and thus, result in lower exposure. Slower shutter speeds allow more time for the sensor to collect light and result in higher exposure.
In this case, the reason we might want to use a higher shutter speed is to stop motion, whether that be a camera shake or a subject that is moving, allowing us to maintain sharpness. Remember, as long as the shutter is open, the camera is essentially recording the position of elements in the frame; if one of those elements moves, the result will often be undesired blurriness.
Many photographers will argue that this is the most important aspect, saying if your shutter speed isn’t fast enough to give you a sharp image, nothing else will save the image. In general, I agree.
SIDE 3: ISO (Image Grain)
Back when film ruled the land, there wasn’t the kind of flexibility in this third side that we have now. You might say the exposure triangle was a two-sided polygon (the geometry of that is another discussion, but I promised this wasn’t a geometry lesson). One could control the sensitivity to light of the film they used, but once the roll was in the camera, there was no changing it (unless you had a swappable back, but these were generally restricted to the medium format world). Nowadays, we can control the sensitivity of the digital sensor on the fly, though technically, we’re not controlling the sensitivity; this actually controls a post-image gain applied to the signal, but for all intents and purposes, you can think of this as sensitivity.
Increasing the ISO essentially allows you to work with less light. As always, though, there’s a tradeoff: increased ISOs result in increased noise and less detail. Noise is the result of random fluctuations in an electrical signal. At lower ISOs, the magnitude of the image signal is large relative to the noise (signal to noise ratio), meaning the noise generally remains unobtrusive. When working at higher ISOs, the image signal is generally close in magnitude to that of the noise and thus, noise enters the image.
Think of the image signal and noise as a pit of balls. If my image signal is 1,000 balls, I won’t notice if noise adds 4 or 5 balls to the bunch. If my image signal is small though, say 10 balls, it will be very noticeable if noise adds 5 balls to the bunch. When I amplify that signal through the use of a high ISO, the relatively high level of noise will be amplified considerably too. When high ISO makes the 10 balls into 1,000 balls again, the noise suddenly becomes 500 balls.
So, why ever use a high ISO? Often, when working in lower light, you will find yourself at a point where you are using the widest possible aperture and the slowest shutter speed you can to stop action. At this point, your only choice is to increase the ISO. The lens cannot physically open itself any wider and as discussed above, sacrificing sharpness for a slower shutter speed is rarely advisable. I would rather have a grainy image that shows a well-defined subject than a smoother image with a subject lost in blur.
WB Rubric
WB Cheat Sheet 1
WB Cheat Sheet 2
Student Sample
Aperture: the opening of a lens, the size of which is controlled by a diaphragm. The term is commonly used to designate f-stops, such as f/4, f/5.6 etc., which are actually arrived at by dividing the focal length of the lens by the diameter of the aperture. Thus, f/11 on a 110mm focal length lens means the opening is 10mm. The wider the opening, the lower the f-number, the more light is let through the lens. Each step in aperture represents a halving or doubling of light. Thus, f/8 allows in half as much light as f/5.6, and twice as much light as f/11.
F-numbers: a series of numbers designating the apertures, or openings at which a lens is set. The higher the number, the narrower the aperture. For example, f/16 is narrower (by one stop) than f/11--it lets in half as much light. An f-number range might be f/2.8, f/4, f/5.6, f/8, f/11...To find the next aperture in a narrowing series, multiply by 1.4. F-numbers are arrived at by dividing the diameter of the opening into the focal length of the lens, thus a 10mm diameter opening on a 110mm lens is f/11. Alternately used with f-stops.
Shutter speed: an element of exposure; the duration of time in which light is allowed to strike the film.
Shutter: in a focal plane shutter, a set of curtains travels past the film gate and allows light to strike the film within a set period of time. A leaf shutter is located within the lens itself.
Speed: with a shutter, the duration of time in which light strikes the film. With film, the sensitivity to light. With a lens, the maximum aperture. All can be described as either fast, medium, or slow speed.
Shutter priority: an auto exposure mode where the shutter speed is user-selected and the exposure system chooses an appropriate aperture for correct exposure.
Iso: a prefix on film speed ratings that stands for an international standards organization, the group that standardizes, among other things, the figures that define the relative speed of films.
Shutter/Aperture Cheat Sheets
PART FIVE - Composition & Rule of Thirds
Composition: the arrangement of subject matter, graphic elements, tones, and light in a scene. It can be harmonious or discordant, depending on the photographer, his or her mood, and the subject at hand.
Contrast: the relationship between the lightest and darkest areas in a scene and/or photograph. A small difference means low contrast; a great difference in high contrast. High-contrast scenes usually cause the most exposure problems; however, their difficulty can mean they hold the potential for more expression.
Depth of field: the zone, or range of distances within a scene that will record on film as sharp. Depth of field is influenced by the focal length of the lens in use, the f-number setting on the lens, and the distance from the camera to the subject. It can be shallow or deep and can be controlled by the photographer. It is one of the most creative and profound effects available to photographers.
Rule of thirds: in the rule of thirds, photos are divided into thirds with two imaginary lines vertically and two lines horizontally making three columns, three rows, and nine sections in the images. Important compositional elements and leading lines are placed on or near the imaginary lines and where the lines intersect.
Foreground, Middleground, Background
Foreground: part of a scene or space around an object that appears closest to the camera. (2) element or feature of the composition of a photograph that is depicted as being the nearest viewer.
Middle ground: is the space located between the background and the foreground in a painting or drawing.
Background: the portion of a scene that sits behind the main, foreground subject. The background can be made sharp or unsharp through the use of selective focusing techniques and depth of field manipulation.
Sharpness: the perception that a picture or parts of a picture are in focus. Also, the rendition of edges or tonal borders.
Crop: to select a portion of the full-frame image as the final picture. Cropping is done in the darkroom or computer environment by the photographer, or by an appointed surrogate in a commercial
KNOW YOUR CAMERA
BASIC CONTROLS
ANSEL ADAMS
MASTER PHOTOGRAPHER
SHUTTER, APERTURE,
AND ISO EXPLAINED