There are hundreds if not thousands of different camera configurations. Because of this it can be daunting to figure out how to use anything more than the Auto setting. Eighty percent of the time, however, I use the same one - Aperture Priority. Aperture Priority mode gives the photographer control over the aperture values and, more-or-less, allows the camera to determine the rest. Most camera manufacturers represent this mode on the dial as 'A' or 'Av. '
Aperture Priority is ideal for portraits, group shots, family, travel and landscapes photos.
The Aperture is the hole in the camera’s lens. The size of the hole influences how much light hits the camera’s sensor. Not surprisingly, a larger opening allows more light to reach the sensor. More often than not, this is a good thing because light is needed to create photographs. The opposite is true for smaller openings. Aperture values are read out in f-stop numbers such as f1.8, f.2.8, f4, and all the way up to f22 (further in some cases). The smaller the f-stop value, the bigger the opening while larger f-stop values shrink the opening resulting in less light hitting the sensor but creating greater depth of field. Let me explain further.
Depth of field is used to describe how much or little the photograph is in focus. A shallow depth of field can be demonstrated in a portrait where the background behind the person is blurred while the subject remains in focus. The opposite effect can be produced as well where there is a lot of depth of field meaning everything in the image is in focus...even the background which, is often desired in landscape or vacation photos.
To see how aperture affects an image, click through the images shown in this post. Notice how the background changes from a blur to being in focus as the aperture values increase. The pictures shot at f1.8 and f2.8 demonstrate a shallow depth of field. While the last couple shot at f16 or f22 demonstrate a lot of depth of field. Also, notice how the ISO jumps from 100 at f1.8 and up to 6400 at f22. This is because as the f-stop values increase, less light is being allowed into the camera which then automatically compensates with higher ISO values. ISO is a digital effect that increases the sensor's sensitivity to light. Higher ISO values also add grain to an image which, is often not desired.
Note: for purposes of demonstrating how Aperture values impact depth of field, I kept the shutter speed at 1/400th to ensure my subject stayed in focus.
Let's breakdown some situations that are well suited for using Aperture Priority mode.
If the goal is to blur the background and isolate the subject which, often makes for a great portrait, then consider using the lowest f-stop value the lens will allow for...this could be as low as f1.2 or as high as f4 or f5.6. To further enhance the blur effect consider these three additional steps:
1) Place the subject as far away from the background as possible.
2) Use a longer zoom such as 100mm or even 200mm lens.
3) Get closer to the subject.
vacation, travel, landscape photography
Often, when taking images of big vistas or other beautiful scenes while on vacation or traveling, the desired outcome is to have the entire scene in focus including the foreground and background so that the image will not only capture your family in the foreground but also capture the details of that beautiful mountain range, lake, or building they are standing in front of. To accomplish this it is best to use a higher f-stop value such as f8, f11, f14 or higher. It is important to remember when using higher f-stop values that less light is hitting the sensor and the camera will lower the shutter speed and increase the ISO values to compensate for this. This is generally OK as many cameras will not let the shutter speed dip too low. or the let the ISO go beyond its practical limits.
As with all photographs, first ask yourself what the desired outcome or intent is. If the intent is to capture a portrait or isolate a subject from its background consider using a low aperture value.. If the intent is to get the background in focus, also use higher f-stop values. If the intent is to freeze action consider using in Shutter Priority mode. More on that in the next blog.
Like all things, the best way to understand these concepts is to practice.
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