PHOTOGRAPHY EXPOSED
PHOTOGRAPHY EXPOSED
by John Peters A.R.P.S.
APERTURE (PRIORITY MODE)
WHAT IS APERTURE (PRIORITY)
I look on APERTURE PRIORITY as one of the most important settings on your camera, giving you the chance to control Depth Of Field (D.O.F.), how much of your subject is in focus. This opens up a new world for us, and allows us to be even more creative with our composition or appearance of the image. It is also a means of adjusting the exposure, but I don't see this as the main function of adjusting the aperture.
BASIC CAMERA WORKINGS
The above diagram is a simplified version of a DSLR. Assume the diagram above is showing a wide open aperture with all the light gathered by the lens / camera but stopped by the mirror / shutter which would swing out of the way at the moment of taking, thus letting the light or photograph reach the sensor. The lens is depicted as being roughly F1.8 as on a standard lens. I won't cover mirrorless cameras which are the latest development in digital camera technology. Other than the viewfinder technology and lack of a prism that is responsible for much of the shape of a DSLR, they work in a similar way. In our example, F11 might indicate a small aperture or a physically smaller hole and F1.8 might indicate a larger aperture or F-stop thus letting more light reach the sensor than if F11 were selected.
Auto mode is also fine, most benefits in photography come by following the simple rules of composition anyway. Reasonably simple editing can rescue photographs that have fallen foul of the weaknesses of the camera's exposure system. I strongly recommend you learn how to bracket your exposures which should cover most exposure errors and for the more advanced photographer, will give you HDR and my EB (search under - E) possibilities in the future .
Above is pictured an older type lens cleary showing the range of apertures and the aperture ring. In this example, the lens can be adjusted from a small aperture of F22 up to a physically larger aperture or hole marked F2.8 On more modern cameras, aperture will probably be displayed in your viewfinder or on your camera or phone screen.
FOR THE BEGINNER
If we imagine that the aperture is simply a part of your lens or camera that forms a space or hole that varies in size, thus controlling the amount of light that reaches the sensor, the piece of your equipment that catches the image. A bigger aperture lets more light through to the sensor than does a smaller aperture. F11 might indicate a small aperture or a physically smaller hole and F1.8 might indicate a larger aperture or F-stop thus letting more light reach the sensor than if F11 were selected.
The priority part implies that from the three variables that many teach to control the exposure, (ISO, APERTURE AND SHUTTER SPEED, sometimes referred to as the Exposure Triangle), you have selected APERTURE mode and have given it PRIORITY over the other modes meaning you set the aperture, the camera usually decides the ISO and the shutter-speed . You might select APERTURE PRIORITY MODE when you want to throw your background out-of-focus, but keep your subject sharply in-focus. This will provide good separation of your subject from the background and will give you a more professional looking photograph.
The most important thing is that you enjoy your photography and that you get satisfaction from looking at your own pictures or those of others irrespective of which mode was used to take them.
As a reminder, Ansel Adams who has made many profound statements on photography, said words similar to "The most important component of your photographic system is the 12" behind it."
The biggest improvement to your photography will come from what you learn about COMPOSITION, NOT by what equipment you use or mode you decide on using, or what exposure is set, please remember this!
Smartphones will be covered under SMARTPHONES and by their design, aperture and DOF behave a little differently from that of a normal DSLR and lens or a compact camera come to that. Depth of field appears greater, and selected shutter speeds appear higher when compared to a DSLR.
TOP TIP Many professional photographers take photographs with the camera set to JPEGS not RAW because they don't want to be boggged down with the time taken converting then selecting JPEGS from RAW. JPEGS are so good for the majority of photographs, they trust JPEGS.
THERE IS NO ONE, SINGLE, CORRECT EXPOSURE
It is almost impossible to define what is the correct exposure. Unless we know the intent of the photographer that took a specific photograph in question, 5 different photographers might come up with 5 different exposure settings.
CREATIVITY AND COMPOSITION
So, taking photographs on auto mode is OK but if you really want to inject some creativity into your work, you should consider COMPOSITION. It's tempting to think, "Oh I need a standard lens, a telephoto lens and a wide-angle lens" but unless your flushed with money, resist the urge to buy more equipment until youve exhausted composition, probably with just your standard lens. The first few elements of composition I prefer to cover are leading lines, rule of thirds, natural framing, giving a moving object space to move into and always, watch your background. Depth of field (DOF) and motion blur can come later along with many other elements of composition.
ADJUSTMENTS TO EXPOSURE OR ADJUSTMENTS TO COMPOSITION
A beginner has enough to grasp and if you're trying to thrust exposure, DOF and motion blur at them all at once, no wonder photography can appear a technical and confusing subject.
Depth Of Field (DOF) controlled by the aperture you set, is that a compositional or technical adjustment made to bring about a particular amount of DOF other than a simple means of making an adjustment purely for exposure? Motion blur or freezing the action, is that a compositional or technical adjustment made to bring about a particular amount of motion-blur other than a simple means of making an adjustment purely for exposure? The truth is, it's both. Aperture priority and shutter-speed priority are major tools that affect the appearance of our image but they also affect exposure as they are part of the exposure triangle.
Remember, there is no such thing as one correct exposure. In my opinion, aperture and shutter-speed offer two of the most influential tools available available to us.
HOW TO SET THE CAMERA TO APERTURE PRIORITY MODE
Select APERTURE PRIORITY mode in the menu or turn the exposure selection dial on the camera / lens to 'A' or Av to make the camera / lens operate in aperture priority mode, effectively letting your camera or phone calculate what SHUTTER-SPEED to use for the exposure. You have given priority to the aperture. Select either a large aperture for a shallow depth of field or a small aperture for a good depth of field on your lens and that's really it. You are using the camera in aperture priority mode - well done.
Above is picture my ideal camera layout. All the controls are dials on the camera or lens for ease of use not having to take the camera from your eye, there is a vari-angle screen to shoot high or low, and an exposure compensation dial to bracket your shots or adjust the exposure. Everthing you need is readily at-hand and no extra menu's need to be navigated. Ideal.
I mentioned Depth Of Field or D.O.F. and we should look at the relationship between APERTURE and D.O.F.
Above is a diagram that shows the relationship between APERTURE and D.O.F. Quite simply, we get more depth of field as the physical size of the aperture gets smaller. Or expressed in a different way:
We could split up our camera's main dial as follows:
Another chart follows, that clarifies the relationship between the different settings and how they influence D.O.F. and MOTION BLUR, two of the most important elements within photography.
Using APERTURE PRIORITY MODE, or one of the other "non-auto" modes allows you more creativity and you can use this fact to create better looking photographs. If we look at a chart illustrating how all the different settings may affect the D.O.F. and motion blur, we get a better idea of the relationship the settings have on the appearance of our image (D.O.F. and motion-blur). Noise can virtually be ignored up to iso 1600 or 3200 with modern day sensors and the use of social media to display images. The chart illustrating noise at high apertures was probably designed years ago and is no longer as accurate.
AUTOMATIC MODE
A camera set to auto or automatic mode will work with the shutter-speed, aperture and using an ISO of it's choice, decide on each setting to produce what it thinks is the correct exposure based on the meter reading. With so many phones just tending to have the one, fixed, maximum aperture, their AUTO mode tends to adjust the shutter speed and keep it fairly high to avoid any shake ruining photographs. Yes ISO may also be readily adjusted but the chances are, a fairly high shutter speed will be selected.
This section is really about APERTURE PRIORITY MODE but if youre a beginner, you may want to stick with AUTOMATIC MODE for now. Let me say that in no way are you any less of a photographer just because you have selected AUTOMATIC MODE or AUTO MODE. The most important thing is that you enjoy your photography and that you get satisfaction from looking at your own pictures or those of others, irrespective of which mode was used to take them.
Automatic mode is relatively hassle free and quite sophisticated now in phones and cameras and automatic mode will make a reasonable exposure most of the time, getting fooled only by awkward situations. Scene modes on some cameras make correct exposure, DOF and motion blur adjustments, that even do away with much of the logic necessary to produce a properly exposed photograph. Scene modes now even encompase elements of composition too.
So, for beginners or painfree photography, why not just set your camera to AUTO OR AUTOMATIC MODE and let the camera or phone work everything out for you. Perhaps there's an element of snobbery attached to using one of the other modes available instead of automatic mode? So what, if you take a few photos at a less than ideal exposure. It's not a crime and no big deal.
BRACKETING (ALL MODES)
If you are in the dark about bracketing, check out "B" or my "EB" method under "B" and "E" respectively. I recommend BRACKETING your shots anyway. One of it's advantages are that it should cover any errors in exposure. Two years down the line, you may wish to produce some photos as HDR photos or even try blending. You may eventually have enough on your hands with selecting and using a particular type of focus and metering, there's often so much to remember but with skill and practise, basic modes or different options can be used.
TOP TIP If you think your subject may trick your meter as it's set, don't rush to change settings, just walk closer to your subject, fill the frame and viewfinder, then use the exposure lock option if your camera has one or just note the settings that are recommended for aperture and shutter-speed. These settings could be used later on to take the photograph if you are not using auto mode.
TOP TIP No matter what mode you are in, set your shutter-speed high enough to freeze the action. The old maxim of 1/focal-length of the lens is a good starting point but with Image Stabilisation coming into play on more modern cameras and lenses, that old rule may not hold but it's a safe starting point.
Back to APERTURE PRIORITY MODE, for a beginner, I recommend settings as follows:
Set ISO at 800 (UK) to give your camera a bigger range of apertures and shutter-speeds than when set at ISO 100. Many people tell you to do to keep noise (digital) or grain (film) at a minimum by setting a low ISO. That's a bit OTT for beginners and old fashioned, just set your ISO to 800, or 400, this is recommended for all modes actually. Even AUTOMATIC MODE. If you are posting to social media such as Facebook or Twitter, or making small prints, don't worry about any references to grain or noise.