Manual and Automatic Exposure (AE) Modes
On most digital camera mode dials, you’ll find a variety of exposure modes, and are divided into two categories; one is preset modes like – sports, night, landscape, portrait, macro etc; other are the creative modes where the Exposure control is in your hand not on the camera.
Here will discuss about the four creative modes to control exposure as we want.
- Aperture priority AE mode (Av)
- Shutter priority AE mode (Tv)
- Program AE mode (P)
- Manual mode (M)
Aperture Priority (Av)
The aperture priority mode enables you to set the f-stop (aperture) and the camera will then automatically adjust the shutter speed to give the correct exposure. This mode is particularly useful in low-light conditions, where you want to set the brightest, widest f-stop in order to get the highest shutter speed and the minimum amount of movement. If more depth of field is needed, you can use a small f-stop to get as much of your picture in focus as possible.
Shutter Priority (Tv)
Using the shutter priority mode, you can set the shutter speed, and the camera will automatically selects the f-stop (aperture) to give the correct exposure. This can be especially useful when you’re shooting action pictures and you want to freeze the motion by setting a high shutter speed. By the same way, if you were photographing a waterfall and you wanted the water to blur, you could set a slow shutter speed and the aperture would adjust accordingly.
Note: These both modes Av and Tv assume that you have enough light to expose your pictures within the range of shutter speeds and apertures you’re using. And if you are not having very proper light or a wide aperture lens then you will have to master the Manual mode and take control of every parameter in your hand.
Program (P)
This setting leaves all the decision-making to the camera. The camera sets a combination of shutter speed and aperture so you don’t have to think about exposure at all. The other fine tune settings are still in your hand but this is moreover an Auto mode from creative zone of mode dial.
In some cameras this may be set up as subject programs such as “portrait,” “sports,” or “landscape.” If there’s not enough (or too much) light to achieve the effect you want then your camera won’t be able to work miracles on this mode. Even on this setting, check the LCD to make sure you are getting the images you want. And remember that you can still use auto exposure compensation to override the camera’s decision.
Manual (M)
This mode allows you to manually set the shutter speed and the aperture independently of each other, referring either to the camera’s built-in exposure meter or to a handheld exposure meter. Professionals prefer to use manual exposure and handheld light meters. Once you will start playing with this mode, you will also enjoy this mode to make some creative photographs. This allows you to take multiple meter readings in various points of the subject frame. In this method the photographer has total control over the pictorial effects that various shutter speed and aperture combinations can achieve. When film was dominant, this method tended to be the exclusive to the professionals or the advanced amateur.
Auto Bracket Settings
Today, the immediate results of digital photography allows you to shoot test frame, have a look, make various adjustment to fine tune the final output and get the right exposure. Most advanced D-SLR cameras have an auto-bracket setting or the HDR(High Dynamic Range) settings. This clever little feature sets the camera to take three pictures automatically, in rapid succession: one at the “correct exposure,” one overexposed, and one underexposed. I find this very useful when working quickly because I know it will give me a choice of exposures after the fact. By setting the camera to shoot one picture at the “correct” exposure—as the camera sees it—and two frames perhaps one f-stop either side, I’ll always end up with one frame that I consider to be the perfect exposure. You can change the increments of the brackets so that they are 1/3, 1/2, or 2/3 stop to either side of the “correct” exposure, depending on the camera model. On most cameras this facility works on all the automatic settings and in manual mode.
Exposure Compensation
If you find that your images consistently look better by underexposing by one stop, or by overexposing by half a stop, then use the exposure compensation setting to build this factor into the camera’s light metering. This you will come to know when you analyse your pictures on the computer screen that your all the images are over-exposed or under-exposed. So, accordingly you can cheat with the camera’s light meter to get your perfect exposure.
This facility enables you to under- or overexpose by up to three f-stops or full shutter speeds. This is normally indicated on your camera by a scale from +3 to -3 with one/third stop increments. Most professional photographers I know use the exposure compensation feature to fine-tune the camera’s light meter. When you have time and the subject permits, vary your exposures so you don’t miss an important shot. Check the images on your computer screen and delete all the bad ones before you show anyone your work.
Picture Squash 