Tuesday, May 17, 2016

Camera Flash Modes

Camera Flash Modes

Auto Flash Mode

The Auto Flash Mode option automatically fires the flash whenever the light level is low for a good exposure or when the main subject is back lit. This setting is the best choice for most shooting circumstances.

Flash On with Red Eye Reduction Mode

This mode is designed to reduce the red eye problem you often see in photographs taken with compact cameras . It works by firing two flashes to minimize red-eye in the subject - first a pre-flash to shrink the iris, and a moment later the actual flash to expose the image. Such features do not guarantee that red eyes are eliminated but rather the chance of it happening is reduced or minimized.
There is also a downside to using a red-eye reduction mode - many subjects blink during the pre-flash, and then the second flash catches them blinking. Or sometimes subjects think that the first flash means the photo was taken and they move and the second flash fires to capture their movement on the photo.
To successfully eliminate red eye, you need an external flash that is positioned away from the axis of the camera lens. If however you do not have an external flash but only a built-in flash, the best strategies are to zoom the lens out to a wider angle, tell the subject to look directly at the camera, try to get close, or increase the overall room lighting.
On most cameras you have the option to turn red-eye reduction mode off.

The Red-Eye Reduction mode is useful when shooting portrait images but in many other situations you might want to turn it off as it does introduce a very brief delay between pressing the shutter button and capturing the image because the red-eye reduction light needs time to flash.

Flash Off Mode

This camera flash mode turns the flash off so that it will not fire even if the light is low. You can instead use a long exposure to capture the image in natural light

Fill-in Flash Mode

With the Fill-in Flash Mode, often called Flash On or Forced Flash , the flash fires every time a picture is taken even if there is enough available light to take the picture without flash.
You will select this camera flash mode when you want to filling in shadows when photographing in bright sunlight or when your subject is back or side lit. In such situations shadow areas can be so dark in the image that they show little or no detail. And when the subject is back lit or against a bright background, it can be underexposed.
Fill flash is also a good way to get accurate color balance under unusual lighting.
Using the fill-in camera flash mode is also very useful when photographing room interiors, which may include a window and where the existing light alone leaves heavy black shadows. If possible, use a powerful flashgun in these circumstances and bounce the light off a suitable wall or surface not included in the picture. This will produce the most even fill-in effect for the scene.

Slow Shutter Flash Mode

In very dim lighting conditions, flash images show a well exposed foreground subject against a black background. The Slow Shutter Flash Mode is designed to minimize this problem by leaving the shutter open longer than usual to lighten the background.
This camera flash mode works by firing a short burst of flash during a longer exposure to freeze objects while still allowing them to blur. If you want to avoid the blur, you will need to use a tripod or use this effect creatively.
This mode is best used for night portraits where the flash lights up the person and the long shutter is used to record the night or city lights.

Slow Shutter Flash Mode

Stroboscopic flash feature is usually set on the flash, not on the camera. It works by firing the flash a number of times at high speed to capture multiple images of the same subject in the same photograph.

This camera flash mode is often used in sports photography for motion studies of a moving subject i.e. golf swing.

High-Speed Sync Flash Mode

This feature is supported in some flash units and you will use it in situations where you want to use a shutter speed that is faster than the camera's flash sync speed. It works by firing numerous rapid bursts of light ensuring that the entire image is illuminated even at extremely fast shutter speeds.

The only drawback is that the feature minimizes the effective flash range so you can't be positioned as far from a subject. The higher the shutter speed you use, the closer you have to be.

Controlling Flash Exposure

Flash Exposure Compensation

Using flash can over or underexpose a subject and it is through the flash exposure compensation that you can manually control the amount of flash light cast over your subject without changing the camera's aperture or shutter speed.
This is an ideal way to balance flash and natural light when using fill flash and to correctly expose scenes or subjects that are darker or lighter than normal. It can give excellent results as it allows you to make more details visible in the shadows, while minimizing the "flatness" that can occur when full flash is used and all the shadows are removed.
The exposure compensation function often lets you vary flash exposures plus or minus 2 stops in one-third stop increments.

Flash Exposure Bracketing

This feature is similar to Autoexposure Backeting. In situations where you might find it difficult to obtain a proper exposure, the flash exposure bracketing allows you to take a series of two or three consecutive pictures exposed at slightly different settings above or below the exposure recommended by the autoexposure system. The flash output changes with each image while the background exposure level remains the same.

Flash Exposure Lock

Flash exposure lock is very similar to AutoExposure Lock and can be used to set the flash exposure for an important subject area in your image.
The feature works by firing a preflash that is used by the light metering system to calculate correct exposure for the primary subject area and the resulting flash settings are locked in. You can then recompose the scene or make exposure or focus adjustments without losing your flash exposure data.
Flash Exposure lock feature is extremely useful when the main subject is off-center or there is a strong back lighting.

Saturday, May 14, 2016

Various Camera Modes and their uses

Types of Camera Modes

Here are the four main types of camera modes that can be found in most digital cameras today:

  1. Program (P)
  2. Shutter Priority (Tv) or (S)
  3. Aperture Priority (Av) or (A)
  4. Manual (M)

1.Program Mode

Program ModeIn “Program” mode, the camera automatically chooses the Aperture and the Shutter Speed for you, based on the amount of light that passes through the lens. This is the mode you want to use for “point and shoot” moments, when you just need to quickly snap a picture. The camera will try to balance between aperture and shutter speed, increasing and decreasing the two based on the intensity of light. If you point the camera to a bright area, the aperture will automatically increase to a bigger number, while keeping the shutter speed reasonably fast. Pointing the camera to a darker area will decrease the aperture to a lower number, in order to maintain a reasonably fast shutter speed. If there is not enough light, the lens aperture will stay at the lowest number (maximum aperture), while the shutter speed will keep on decreasing until it reaches proper exposure.
I personally never use this mode, since it does not give me much control over the exposure. There is a way to override the camera-guessed shutter speed and aperture by moving the control dial (on Nikon cameras it is the dial on the back of the camera). If you rotate the control dial towards the left, the camera will decrease the shutter speed and increase the aperture. If you rotate the dial towards the right, the camera will increase the shutter speed and decrease the aperture. Basically, if you needed to get a faster shutter speed for freezing action, you would rotate the dial to the right, and if you needed to get a large depth of field, you would rotate the dial to the left.

2.Shutter-Priority Mode

Shutter-Priority Mode
In “Shutter Priority” mode, you manually set the camera’s shutter speed and the camera automatically picks the right aperture for you, based on the amount of light that passes through the lens. This mode is intended to be used when motion needs to be frozen or intentionally blurred. If there is too much light, the camera will increase the lens aperture to a higher number, which decreases the amount of light that passes through the lens. If there is not enough light, the camera will decrease the aperture to the lowest number, so that more light passes through the lens. So in Shutter Priority mode, the shutter speed stays the same (what you set it to), while aperture automatically increases and decreases, based on the amount of light. In addition, there is no control over subject isolation, because you are letting the camera control the depth of field.
I try not to use this mode either, because there is a risk of getting an overexposed or underexposed image. Why? Because if the amount of ambient light is not sufficient and I set the shutter speed to a really high number, my exposure will be limited to the aperture/speed of my lens. For example, if the maximum aperture of my lens is f/4.0, the camera will not be able to use a lower aperture than f/4.0 and will still shoot at the fast shutter speed that I manually set. The result will be an underexposed image. At the same time, if I use a very slow shutter speed when there is plenty of light, the image will be overexposed and blown out.

3.Aperture-Priority Mode

Aperture-Priority Mode

In “Aperture Priority” mode, you manually set the lens aperture, while the camera automatically picks the right shutter speed to properly expose the image. You have full control over subject isolation and you can play with the depth of field, because you can increase or decrease the lens aperture and let the camera do the math on measuring the right shutter speed. If there is too much light, the camera will automatically increase the shutter speed, while if you are in a low-light environment, the camera will decrease the shutter speed. There is almost no risk of having an overexposed or an underexposed image, because the shutter speed can go as low as 30 seconds and as fast as 1/4000-1/8000th of a second (depending on the camera), which is more than sufficient for most lighting situations.
This is the mode that I use 95% of the time, because I have full control over the depth of field and I know that the image will be properly exposed under normal circumstances. The metering systems in most modern cameras work very well and I let the camera calculate and control the shutter speed for me.

4. Manual Mode

Manual Mode

As the name suggests, “Manual” mode stands for a full manual control of Aperture and Shutter Speed. In this mode, you can manually set both the aperture and the shutter speed to any value you want – the camera lets you fully take over the exposure controls. This mode is generally used in situations, where the camera has a hard time figuring out the correct exposure in extreme lighting situations. For example, if you are photographing a scene with a very bright area, the camera might incorrectly guess the exposure and either overexpose or underexpose the rest of the image. In those cases, you can set your camera to manual mode, then evaluate the amount of light in darker and brighter areas and override the exposure with your own settings. Manual mode is also useful for consistency, if you need to make sure that both shutter speed and aperture stay the same across multiple exposures. For example, to properly stitch a panorama, all shots that you are trying to put together need to have the same shutter speed and aperture. Otherwise, some images will be darker, while others are lighter. Once you set the shutter speed and aperture to the values of your choice in manual mode, your images will all have consistent exposures.
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