Sunday, April 30, 2006
EV Compensation in Digital Camera
The light meters of cameras cannot see color. The automatic exposure system renders the values in every scene to balance to an 18% neutral gray and determines the exposure accordingly. In most of the situations, this would work well. But in difficult lighting conditions exposure value compensation setting has to be used to over ride the camera’s automatic exposure setting. EV Compensation will be much helpful in scenes such as ‘ a white cottage surrounded by snow’ or ‘a black cat in a dark background’. Adjusting the setting in such conditions will help you capture the image the way it looks. By increasing the compensation the distinct brightness of the white object in a white background gets restored. When compensation is decreased, the distinct tones of the black image get highlighted in a black background.
A contrast problem may crop up when the difference between the most dark and the rest or the most white and the rest exceeds the range of the camera. In such conditions you should choose the area, which needs detailed capture. You may have to increase compensation to increase detail in shadows or decrease compensation to increase detail in highlights. In certain cases, additional lighting may improve the situation.
Setting
The default setting for EV Compensation is ± 0. Digital Cameras normally have provision to compensate the exposure by 1 to 2 EV plus or minus by increments of 1/3.The following guidelines may help you to experiment and gain experience,
1.When the subject to be captured is backlit with very bright light, the setting can be +0.7 or +1.0
2.When bright sunlight from behind you makes the subject very bright, the setting can be –0.3 or –0.7
3.For a scene with a normal sunlight and/or backlighting the range of 0.0 to +2 should be considered; so also in a beach or for conditions of dimly lit night sky or snow.
4. For capturing sea view or landscape just prior to dusk a setting of –2/3 may give good results.
5.When you have to capture dark objects placed in similar surroundings, a setting from –1 1/3 to –2 /3
may be adopted.
6. To have a close up capture of light colored flowers or similar objects, choose a setting in the range of +1/3 to 1 2/3
EV compensation gets reset to its default value when camera is turned off.
Effecting change of mood
You may like to alter the mood of the scenes sometimes, by making it brighter or darker than what it really looks. EV Compensation is an effective tool to achieve this.
To brighten your photograph being taken on a dull day, you can increase the setting and bring about an artistic tone. By decreasing the exposure value, a sober effect on an otherwise bright scene can be created or the effect of thoughtful look in an individual can be made more impressive.
Automatic settings may overexpose twilight scenes. The real life in the dark areas may get lost. Suitable decrease in exposure value will enrich the life of the scene captured.
A contrast problem may crop up when the difference between the most dark and the rest or the most white and the rest exceeds the range of the camera. In such conditions you should choose the area, which needs detailed capture. You may have to increase compensation to increase detail in shadows or decrease compensation to increase detail in highlights. In certain cases, additional lighting may improve the situation.
Setting
The default setting for EV Compensation is ± 0. Digital Cameras normally have provision to compensate the exposure by 1 to 2 EV plus or minus by increments of 1/3.The following guidelines may help you to experiment and gain experience,
1.When the subject to be captured is backlit with very bright light, the setting can be +0.7 or +1.0
2.When bright sunlight from behind you makes the subject very bright, the setting can be –0.3 or –0.7
3.For a scene with a normal sunlight and/or backlighting the range of 0.0 to +2 should be considered; so also in a beach or for conditions of dimly lit night sky or snow.
4. For capturing sea view or landscape just prior to dusk a setting of –2/3 may give good results.
5.When you have to capture dark objects placed in similar surroundings, a setting from –1 1/3 to –2 /3
may be adopted.
6. To have a close up capture of light colored flowers or similar objects, choose a setting in the range of +1/3 to 1 2/3
EV compensation gets reset to its default value when camera is turned off.
Effecting change of mood
You may like to alter the mood of the scenes sometimes, by making it brighter or darker than what it really looks. EV Compensation is an effective tool to achieve this.
To brighten your photograph being taken on a dull day, you can increase the setting and bring about an artistic tone. By decreasing the exposure value, a sober effect on an otherwise bright scene can be created or the effect of thoughtful look in an individual can be made more impressive.
Automatic settings may overexpose twilight scenes. The real life in the dark areas may get lost. Suitable decrease in exposure value will enrich the life of the scene captured.
Tuesday, April 11, 2006
Exposure Metering in Digital Camera
The three different settings provided for AE Metering, enables you to choose the part of the image the camera should use for measuring brightness and contrast to determine the exposure.
Multi-Segment
Samples from all parts of the image in the entire screen are reckoned to determine the exposure when this setting is selected.
Center – Weighted
This setting measures brightness and contrast in the central region of the image and decides the exposure.
This works well when the subject image falls in the center of the frame.
Spot
A small area only in the center of the screen is reckoned. The subject is to be centered in a spot in the center of the viewfinder. This setting is useful in backlit scenes or when the subject is very dark or light compared to the rest of the scene.
The default setting for Green Mode is Multi-segment Metering.
Saturday, April 01, 2006
Sensitivity and Sharpness in Digital camera
Sensitivity
You know that there are specific ISO settings in film cameras corresponding to different slow and fast speed of films or sensitivity of films. Slow speed films are used for bright light conditions and fast films for
conditions of low level lighting. You may also know that provision for automatic change of ISO setting on recognizing the sensitivity of the film loaded is also available in many cameras.
In digital cameras the sensitivity of the CCD is automatically adjusted. If you increase the sensitivity the images captured are likely to be overridden by noise.
The CCD sensitivity setting may range from ISO25to ISO 1600.Manual setting is also normally provided.
The need for manual setting may arise in low-level light conditions. Use of tripod is essential in such cases.
The working range of flash is normally reckoned with standard output sensitivity of ISO 200. Increasing ISO range also increases the working range of flash.
In case of a close up of, say a flower moving along the wind breeze, if you have made the aperture small to ensure maximum depth of field, the resulting slow shutter speed may result in a blurred image. If you increase the ISO setting now, the aperture and shutter speed will increase and capturing the image in a moment of freeze becomes possible.
In most of the situations, it is always desirable to keep a standard lower sitting and auto option ‘on’ in the camera’s menu.
Certain broad guidelines for ISO setting are given below.
Auto ISO is ideal for most of the situations.
ISO 80 may be chosen in bright light conditions for close ups, portraits and landscapes. Detailed and fine image quality can be expected.
ISO 100 may give a little less of image quality.
ISO 200 may be chosen for cloudy days. Image quality will be good.
ISO 400 and above will be the choice for in door photography and sports photography. High noise levels are to be expected.
Sharpness
The sharpness setting helps you to shift from a normal position to a sharp or soft setting when you want to have sharper outlines with increased contrast on the edges of the image or softer outlines. The sharp setting may be chosen in the case of edge of a building against the sky. The soft setting, which softens the edges, is chosen to create an ideal soft focus effect in portraits.
A normal setting is generally desired.
Saturation
A saturation setting is intended to add vibrancy to all colors. A normal setting keeps up balanced saturation with natural looking colors. Setting enables an increase or decrease in saturation.
