Casper College, 3/21/19
Instructor: Karel Mathison
- Polarizing Filter Demo
- Focus Selector
- Metering Mode
- Picture Controls
- Retouch Menu
Polarizing Filter Demo
This was an outdoor demo using two different subjects viewed at a 90° horizontal angle from the sun. The 90° angle is the point of maximum polarizing effect. More acute or obtuse angles have a diminished effect.
Viewing the horizon and rotating the CPL filter, which selects the direction of polarization, deepens the sky’s blues and reduces haze. Karel also told us that it makes the clouds standout better. This couldn’t be part of the demonstration because there weren’t any clouds.
The second subject we looked at was a brightly lit snow bank. The polarizing filter reduces glare off the snow drawing out the contrasts and contours more effectively.
Two controls affect focus selection, focus mode and autofocus area mode.
The focus mode determines how the camera’s autofocus motors are controlled. There are several choices that change depending on whether the camera is in view finder or live view mode.
View Finder Options
- Single-servo autofocus (AF-S). Pressing the shutter release half way down causes the camera to focus the lens. This focus point will be held even if the camera is moved to point to a different subject as long as the shutter release button is held at least half way down. This is good for static subjects. Artifacts at the weave points in panoramic images are avoided by maintaining the same focus throughout.
- Continuous-servo autofocus (AF-C). The camera will continuously refocus when the shutter release is held down. When taking a picture of a moving object in continuous shuttering mode, holding the shutter release down will result in a sequence of images being taken. If the camera is also in AF-C mode, the camera will refocus between each image.
- Auto-servo autofocus (AF-A). The camera will automatically evaluate the image to determine whether there is motion. If so, it will switch to AF-C mode; otherwise, AF-S will be used. The camera won’t always select the optimal focus mode. Consider taking a picture of a bird in a tree on a day with a light breeze that’s moving the leaves around. The photographer likely wants to focus on the bird, which is static, making AF-S the preferred mode. However, the camera may detect the leaves moving and switch to AF-C causing the bird to be slightly out of focus.
- Manual focus. This is exactly what you would expect. The photographer must turn the focus ring on the lens to focus the image.
Live View Options
- Single-servo autofocus. This is exactly the same as described above.
- Full-time servo autofocus. The camera continuously adjusts its focus until the shutter release is pressed half way down. The press locks the focus in place.
- Manual focus. This is the same as described above.
The other autofocus control is the area mode. The area mode provides a clue to the camera on how to optimally focus by indicate what part of the scene to focus on. The options also differ between view finder and live view. The available options are also abbreviated in AF-S.
View Finder Options
- Single point AF. In single point AF, only one point in the scene is used to determine the optional focus. My camera has eleven points that the photographer can select among as the focal point. Only one can be selected at a time.
- Dynamic area AF. A single point is selected as the focal point the same as in single point AF mode. The difference is that the camera also incorporates information from surrounding points when focusing. This is useful when photographing a moving subject that may not remain exactly on the selected focus point.
- 3D tracking AF. 3D tracking uses color information to identify a moving subject and automatically move the focal point to track the subject.
- Auto-area AF. A combination of color information and facial recognition software is used to automatically focus on faces.
Live View Options
- Face Priority. This is similar to the auto-area AF mode above.
- Wide area AF. The photographer selects an area of the scene for optimal focus. The camera uses information throughout that area when focusing.
- Normal area AF. This operates the same as wide area focus except that the selectable area is smaller.
- Subject tracking AF. This mode is similar to the 3D tracking AF mode when in view finder. It’s optimized to track a moving subject.
Metering is measuring the light entering the camera to automatically adjust the exposure. When in aperture priority mode, the camera will adjust the shutter speed and ISO setting. The aperture size and ISO setting will be adjusted when the camera is in shutter priority mode. Metering does not apply to manual mode. The photographer is on their own in that mode.
To facilitate getting the desired exposure, the photographer can provide a clue to the camera by changing the metering mode. My camera has three options.
- Matrix metering. Light from the entire scene is evaluated to determine the optional exposure.
- Center-weighted metering. Light from the focal points and immediately surround parts of the scene determine the exposure.
- Spot metering. Only the focal point is used to determine the exposure.
Picture control provides additional help to the camera to determine how various colors should be interpreted when the image is produced. This only works for the JPEG images. The RAW images (aka NEF) contain everything. To produce these effects with RAW, the images must be processed on the computer. Available options include:
Discussion of the retouch menu was limited almost entirely to a recommendation not to use it. Karel said that you’re almost always better off retouching images on the computer. The software is more powerful and the screen is big enough that you can see what you’re doing. Nonetheless, there are many options available and they vary dramatically among camera models.
Photography is one of those hobbies where you can spend lots and lots of money buying extra stuff. Karel brought out some of her favorites.
- Tripods & Monopods.
- L Brakets. These mount on the tripod and monopod heads and allow the camera to be positioned in either portrait or landscape mode while keeping its center of gravity directly above the supporting post.
- Remotes. Karel recommends wired remotes over wireless because they’re more reliable. These are useful to eliminate camera shake.
- Head Lamp. While not really camera equipment, Karel recommends them when photographing in low light situations so that your hands are free while making camera adjustments. She also strongly recommends using the ones with a red light to avoid messing up dark vision.
- Camera Coat. These are similar to hand muffs that allow a camera to fit inside. They keep the hands warm when photographing in cold weather.
- Rapid lens changer. This is a carrying mechanism for lenses. It’s designed to allow you to quickly change lenses in the field without having to dig them out of your camera bag.
Anything by the following authors was recommended.
- Scott Kelby – Most of his stuff is about software like Photoshop or Lightroom.
- Douglas Klostermann
- Laurie Excell
- Matt Kloskowski
Karel also said that camera-specific ebooks are also usually pretty good.