Semi-automatic modes give you more creative control over the various elements of your photos than full auto, but without throwing you into full manual mode. Choose what factor you wish to control — depth of field, shutter speed — and pick a semi-automatic mode that takes care of the rest. In these various semi-automatic modes, there are other settings beyond exposure that are also left up to the photographer. It is often up to you to choose an appropriate ISO number, however many Sony Alpha DSLRs also offer auto-ISO.
Focusing and metering are also important settings — you choose which AF mode to use, and which mode to use in order to meter light in the frame.
Aperture Priority Mode (A)
Understanding aperture is probably the most difficult setting for most people to grasp, but once you understand it, it perhaps the easiest (or most popular) mode to use for many photographers. The aperture is an adjustable opening in the lens that controls the amount of light that can enter the camera. The aperture setting is expressed in f stops with the largest opening having a smaller number so a wide open aperture is going to have an f-stop of around f1.4.
The aperture setting can have a big effect on the depth of field which allows one part of the image to be in focus and the rest of it being blurry which helps to highlight the subject of the photograph. As a result most people use Aperture Priority Mode when they are attempting to have some control of the depth of field. When choosing an Aperture keep in mind that the camera will be choosing faster or longer shutter speeds and that there comes a point where shutter speeds get too long to continue to hand hold your camera (usually around 1/60). Once you get much slower than this level you’ll need to consider using a tripod. Also if you’re photographing a moving subject your shutter speed will impact how it’s captured and a slow shutter speed will mean your subject will be blurred).
In Aperture Priority mode, you set the aperture and the camera determines the rest of the exposure settings automatically. Aperture priority mode is useful for creatively using depth of field or choosing an aperture that is optimal for low-light shooting (or blocking out ambient light) without worrying about the shutter speed. For example:
• Choose a large aperture (low f number) for a shallow depth of field, such as 2.8 or 1.4. This will give you a blurry, out-of-focus background.
• Choose a small aperture (high f number) such as 10, 16 or 22 for a deep depth of field that will put much more of your subject in focus. This is often useful for landscape photos.
• Choose a large aperture to shoot hand-held in low light. The wider aperture allows more light to hit the sensor, enabling you to use a shutter speed fast enough to photograph a person or eliminate blur resulting from shaking hands.
Shutter Priority Mode (S)
The shutter speed is one of the easiest settings to understand as it simply means how fast the shutter opens and closes when you press the shutter button. The faster the shutter speed the better the camera will freeze the action of an event. This setting is represented in seconds, a fast shutter speed would be something like 1/2000th of a second. A long shutter speed such as 1/30th of a second or slower can result in blurry images if you don’t use a tripod. Like the other settings, the shutter speed also affects the amount of light that hits the sensor. The faster the shutter speed, the less light that comes into the camera. So while a fast shutter speed can freeze action, you need more and more light in order to prevent getting a dark picture the faster you set the shutter. When you cant get a bright enough image, you will need to slow down the shutter speed. In some cases you may want to get a motion blur such as a waterfall or freeway traffic, these shots require a very long shutter speed.
In Shutter Priority mode, you set the shutter speed and the camera determines the rest of the exposure settings automatically. An example of a situation where this is applicable is sports — use your DSLR’s shutter priority mode to set a fast motion-stopping shutter speed, and let the camera automatically choose the other necessary settings for a good exposure.
• Choose a fast shutter speed such as 1/1000 of a second to freeze the motion of a fast-moving athlete.
• Choose a slower shutter speed to create motion blur, e.g. photograph fast-moving traffic as streaks of red and white (tail and headlights).
A camera that has been set to one of these semi-automatic modes usually will not fire the flash unless you specifically ask the camera to do so — either by manually activating or popping up your built-in flash, or attaching and turning on an external flash .
Manual mode allows you to set both your aperture and shutter speed separately, without the camera automatically changing the other to suit. With this in mind, you can be more creative with your shots.
Manual mode gives you full control over your exposure. If you are finding a lot of your photographs are either underexposed (too dark) or overexposed (too light) then working in fully manual mode will help you to better understand and correct these exposure problems.
Using manual mode is much easier than most beginner photographers think it is.
A common misconception is that manual mode means you need to set all of the cameras settings such as aperture, shutter speed and iso manually. Due to the huge number of combinations possible of just these three settings this can seem like an impossible task.
However, the camera’s manual mode will advise you of the best settings to use for a particular scene. Based on this advice you can either do as it recommends or make minor changes to the settings in order to get better exposures in certain situations when you know that the camera will get it wrong.
Simple steps to using Manual Mode
More often than not you’ll want to select a specific shutter speed or aperture as a starting point. You may want to start with aperture if you want to control depth of field, such as to blur the background for a portrait (say, f5.6), or to keep everything in focus for a landscape photo (say, f22). Alternatively You might start with shutter speed if you’re attempting to freeze fast actions (such as motorsports) or blur movement (such as waterfalls).
Assuming you start with aperture, once you have selected your aperture simply point your camera at your subject. Your camera will then monitor the light levels reflecting off your subject and indicate what shutter speed is required in order to obtain what it thinks is a correct exposure. Adjust the shutter speed using the dial on your camera until the little mark on the scale sits in the middle of the scale. Now take your shot and you should have a correct exposure. Simple!
While this may sound like more effort than using a Priority mode or an Auto mode, the real benefit of manual mode comes when the camera is struggling to meter light correctly, or in the way you want. For example, shooting a portrait with a large amount of brightly lit background (such as snow) can result in correct correct metering of the snow but not the person you want to feature. With manual mode it is very easy to adjust your exposure level by changing the shutter speed or aperture, while keeping the other constant. Exposure compensation in the Priority modes has a similar effect, but is limited.
Memory Recall modes (1, 2, 3, MR)
Some models (Konica Minolta 7D, Sony Alpha a700, a850, and a900) have memory positions for stored settings. This can be useful if you wish to use commonly set adjustments for specific scenarios.