Starting at 7:00pm ET before the MichiganOne DMR Tech Net, Bob KB8DQQ and James N8TMP will discuss the very popular amateur radio hobby of photography. Tune in to learn more about DSLR, mirrorless, and mobile cameras. They will discuss features, techniques, photography terms, and skills on BrandMeister talkgroup 31266, the Michigan Nets channel. You can chat and ask questions with them until 7:30pm when the MichiganOne DMR Tech Net begins.
F-stop / Aperture
In photography, f-stop, or aperture, refers to the setting on a camera lens that controls the size of the opening through which light passes to reach the camera’s sensor. It’s a crucial element in photography, affecting both the brightness and the depth of field (the area in focus) in an image.
Here’s a more detailed explanation:
- How it works:
The f-stop is expressed as a number (e.g., f/2.8, f/8, f/16). A smaller number (e.g., f/2.8) indicates a wider aperture, allowing more light to enter the camera. Conversely, a larger number (e.g., f/16) means a smaller aperture, restricting the amount of light.
A wider aperture (smaller f-number) results in a shallower depth of field, meaning only a narrow range of distances will be in focus, with the background often appearing blurred. A smaller aperture (larger f-number) creates a greater depth of field, where more of the scene, from foreground to background, will be in focus.
- Exposure:
F-stop is one of the three elements of the exposure triangle (along with shutter speed and ISO) that determine how bright or dark an image is.
- Common f-stop ranges:
Lenses typically have a range of f-stops they can support. Common ranges include f/1.2-f/2.8 for low-light situations and shallow depth of field, f/4-f/8 for general use, and f/11-f/32 for landscape photography where a large depth of field is desired.
- Practical application:
Portrait photographers often use wider apertures (lower f-numbers) to isolate their subjects and blur the background, while landscape photographers typically use smaller apertures (higher f-numbers) to keep the entire scene in focus.
Shutter –
Shutter speed in photography refers to the length of time the camera’s shutter is open, allowing light to reach the sensor and create an image. It’s measured in seconds or fractions of a second, and it’s one of the three key elements of exposure, along with aperture and ISO. A faster shutter speed means the shutter is open for a shorter time, capturing less light and potentially freezing motion, while a slower shutter speed means the shutter is open longer, capturing more light and potentially blurring motion.
Here’s a more detailed explanation:
- Freezing Motion:
Fast shutter speeds (e.g., 1/500th of a second or faster) are used to freeze fast-moving subjects, like athletes in action or birds in flight.
- Blurring Motion:
Slower shutter speeds (e.g., 1/30th of a second or slower) can be used to create intentional motion blur, which can be a creative effect, especially for subjects like flowing water or moving vehicles.
- Light and Darkness:
A fast shutter speed lets in less light, resulting in a darker image, while a slow shutter speed lets in more light, resulting in a brighter image.
- Camera Shake:
When using slow shutter speeds, especially handheld, camera shake can become a problem, leading to blurry images. Tripods or other stabilization techniques are often needed for long exposures.
- Examples:
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- Fast:A photo of a racing car might use a fast shutter speed to freeze the car’s motion.
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- Slow:A photo of a waterfall might use a slow shutter speed to create a silky smooth effect of the flowing water.
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- Slow (with blur):A photo of a crowd of people walking might use a slow shutter speed to show the motion of the crowd.
ISO –
In photography, ISO refers to the sensitivity of your camera’s sensor to light. It’s one of the three elements of the exposure triangle, along with aperture and shutter speed. A higher ISO means the camera is more sensitive to light, allowing you to shoot in darker conditions, but it can also introduce noise or grain into the image. Conversely, a lower ISO results in cleaner images but requires more light.
Here’s a more detailed explanation:
Higher ISO values (e.g., 1600, 3200) mean the camera’s sensor is more sensitive to light, enabling you to capture images in darker environments. Lower ISO values (e.g., 100, 200) mean the sensor is less sensitive, requiring brighter conditions or longer exposure times.
While higher ISO allows for shooting in low light, it often introduces “noise” or “grain” into the image, which appears as small, speckled dots, particularly noticeable in darker areas of the photo.
Understanding the relationship between ISO, aperture (the size of the lens opening), and shutter speed (how long the camera sensor is exposed to light) is crucial for achieving proper exposure and desired image quality.
When shooting indoors, at night, or in other low-light situations where you can’t use a flash or slow down your shutter speed significantly, increasing the ISO can be necessary to capture a usable image.
In bright light, like outdoors on a sunny day, you can keep your ISO low to minimize noise and achieve the cleanest possible image.
Some photographers intentionally use higher ISO settings to create a grainy or artistic effect, adding mood or nostalgia to their photos, according to a video tutorial on YouTube.
.The concept of ISO originated with film photography, where it represented the film’s sensitivity to light. Digital cameras use the same ISO numbering system to indicate the light sensitivity of the sensor.
