Photography Basics Part 3 - Exposure Modes

Photography Basics Part 3: Understanding Exposure Modes

It had occurred to me that as I have been explaining some camera basics, it might be useful to also explain the basic exposure modes that all DSLR (and many point and shoot) models will have. Using these modes properly will greatly enhance your photos and will give you much more creative control compared to the ‘Auto’ mode.

In auto mode, the camera controls all of the basic functions associated with capturing the image. The two most basic variables associated with exposing and images are the Shutter Speed and the Aperture. Allowing the camera to choose the exposure settings isn’t always a poor decision, but for the vast majority of the time, you will see an improvement in your images when you take more control over the settings that are used. To do this, you must first understand how the Aperture, Shutter Speed, and ISO relate to each other. If you need more clarification as to what these settings are, please read Photography Basics Part 1 – The Basics of Exposure.

Once you`ve got a solid understanding of the basics of exposure, you can start to utilize the various semi-automatic and manual settings on your camera. The following photo shows the various settings available on the Nikon D7000 (the camera I am currently using). I will discuss 3 of the most common modes in this article.
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Original Photo of D7000 Mode Dial was taken from Nikon D7000 Review | Wex Photographic and was then modified by me for use with this article.

Note: I will be speaking from a Nikon owner’s point of view as that is my area of expertise. Canon and other manufacturers may use slightly different terminology/settings, so it is up to you to research any differences that may exist between brands. Sorry for any confusion.






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Aperture Priority (A)

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Aperture Priority mode is what I refer to as a “semi-auto” mode, meaning the user controls some features and the camera controls the rest. In this mode, the user is able to set the aperture value and the camera will automatically choose a shutter speed to corresponds to what it thinks is the proper exposure. As you should already know, the aperture value determines your depth of field. For an in-depth look at Depth of Field, please see Photography Basics Part 2 – Depth of Field.




When To Use Aperture Priority Mode
Aperture priority mode can be useful in a number of situations. Remember, your aperture controls the depth of field of your image, so you most likely want to use this mode when depth of field is your top priority of your image.

Landscapes, for instance, are a great time to use aperture priority mode. When shooting landscapes, you usually want to make sure your scene is in focus, therefore setting your aperture to setting that will produce the necessary depth of field is crucial.

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Portraits, on the other hand, are often captured with a shallow depth of field to isolate your subject and product a very nice looking photograph. This is another great time to use aperture priority mode.

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Shutter Speed Priority (S)

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Shutter Speed Priority Mode is also a “semi-auto” mode. In this mode, the user can set their desired shutter speed and the camera will determine the necessary aperture value for the optimal exposure according to the ISO value that has also been selected.





When To Use Shutter Speed Priority Mode
As you should already be aware of, shutter speed controls the motion blur (or lack thereof) in the image. Shutter priority is a great choice when you’d like to introduce motion blur by setting a slower shutter speed or when you want to freeze motion by setting a faster shutter speed.

Sometimes, motion blur can add an attractive and creative effect to your photos. One of the ways I like to use motion blur is in automotive photography. By panning the camera along with a moving vehicle, and also using a slow shutter speed, you can capture motion by displaying a blurred background (note: not the same as a blurred background from a shallow depth of field) and blurred wheels as seen in the following photo.
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f/5.6, 1/30 sec, ISO320

Action sports are a great example of when you usually want to freeze the motion to eliminate any blur. In this instance, you must choose a fast enough shutter speed so that any objects in motion are frozen in time while the photo is taken.
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f/5.3, 1/1000 sec, ISO160





What is Exposure Compensation?

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Original Photo of D7000 LCD screen area is from KenRockwell.com: Photography, Cameras and Taking Better Pictures. This photo was also modified for use with this article.


Exposure compensation is a tool that allows you to further adjust your images while you are using one of the “semi-auto” modes. Since you are still allowing the camera to choose settings for you, you do not have complete control over the exposure. In certain instances with difficult lighting, the most common example being strong back lighting, you can use exposure compensation to make your images brighter (increase exposure) or darker (decrease exposure).

Let me explain how this works. Suppose you are going to take a picture of your subject, but they are standing in front of a window. The window is very bright because it is a nice sunny day outside. When you take the photo, chances are your friend will appear mostly as a silhouette (i.e. a black shape) as seen in the following image.

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The reason behind this is that your camera is adjusting for that strong back lighting by evening out the exposure of the entire image. The dynamic range of cameras is simply not able to pick up both the extreme highlights of the bright outside area and the dimly lit face of your subject. Since your camera does not know that you want to see your friend, and do not care about what is outside, it simply adjusts for what it considers ‘optimal overall exposure’ for the entire scene. In order to adjust for this, you can increase the exposure by using the exposure compensation.

For this example, you would need to increase the exposure and then take another photo to see if that produces your desired results.

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You will notice that the bright window area is now completely white (or at least much brighter than it was in the original photo) and your subject is properly exposed.

Using Exposure Compensation is very similar to shooting in full manual mode. Say, for instance, that you have you camera set to Aperture Priority with an aperture of f/5.6 and you camera thinks the best shutter speed is 1/200 second. However, after you review the image you realize you need to brighten the image and decide to dial in one stop of exposure compensation (+1), all your camera is doing is then changing the shutter speed to 1/100 second to add that extra light to the photo. This is essentially the same thing that you can do on your own when shooting in full manual mode.

Note: This is example is assuming you are using matrix metering mode. If you are using spot metering, you may not have needed exposure compensation in this example. Metering is not covered in this article, so I will not go into detail on that subject at this time.





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Manual (M)

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When using manual mode, the photographer has complete control over both the shutter speed and aperture. There is no need for exposure compensation because you can simply manipulate your settings to control the exposure. For instance, using the same example as above, if your subject is standing in front of a bright window, you could simply lower your shutter speed or open your aperture to properly increase the exposure for the scene to your liking despite what your camera’s meter is telling you.





When To Use Manual Mode
I use manual mode for the vast majority of my shots. I enjoy having complete control of my settings and not having to worry about the camera selecting any of my settings. With practice, manual mode is a very efficient way to shoot and you will be able to change settings quickly and easily to produce the best exposure for your creative eye. I find I get more consistent results when using manual exposure mode vs. one of the semi-auto modes, however there are still times when I find the semi-auto modes to be very, very useful.




Review
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All of these settings open worlds of creativity for your photography when compared to auto mode. Learning to use these semi-automatic and manual exposure modes is absolutely critical in maximizing your camera’s potential. You’ll find that it really is not that hard to produce amazing images once you start to understand The Basics of Exposure and how to manipulate the corresponding settings by experimenting with various exposure modes.


As always, thanks for reading!

Please feel free to post any questions. Myself or another photo savvy reader will be more than happy to help you out :dblthumb2: