Learning to Become a Photographer - Exposure and Modes


“This article is the first in a series of articles that will guide you through a mentorship program where I hope to answer any questions you might have about photography.

Which type of camera are you using?

This does not mean that I want to know the brand of your camera, such as Nikon or Canon. It is only asking about the type. You probably have a point-and shooter if your camera doesn’t allow you to remove its lens. This is a name for a camera that has its lens permanently attached to its body. It is limited to one lens, the one attached to it. For situations such as photographing distant objects and wide landscapes, this will limit your options for focal lengths. You can detach the lens with your camera if your camera supports it. This is a good option. DSLRs can be used to mount a wide variety of lenses, from ultra-wide to super-telephoto. Lens interchange allows you to change focal lengths from 8mm up to 1200mm.

Are brands important?

Yes and no. Brands do matter if you’re deciding whether to buy a Texas Instrument DSLR camera or a Nikon. If you’re stuck between Canon or Nikon, your purchase won’t come down to brand but personal preference.

What is a Megapixel?

Pixels are the measurement of the size of your digital image. Mega is the prefix that stands for million. It’s therefore one million pixels. A digital image can be measured in both vertical and horizontal dimensions. Your camera manual may state that it can create 16 Megapixel images. It is only stating that the image is 4,928 pixels by 3,280 pixels. A computer monitor can display 72 pixels per inch of an image, while a printed image will need 200 pixels per inch. These pixels are consumed as you create more images. Pixels do not exist in a vacuum. It is better to have more pixels that you don’t need.

An explanation of exposure

Let me begin by explaining that visible lighting is what creates images in our retina. A camera’s retina can be described as a sensor in the same way. An image is formed when light hits the sensor through the lens. This sounds simple, but it requires proper management of visible light rays (which we will call ‘light’). Overexposed images will result if there is too much light reaching your sensor. A camera that receives too much light will produce an overexposed image.

Two components are essential to your DSLR. The shutter is the first. This is a movable curtain which sits in front of the camera’s sensor. It only retracts during exposures to let light through. The aperture is the second component. The aperture is made up of several blades within a lens that form an aperture opening. The aperture value determines the diameter of this opening. The camera controls the speed and opening of the aperture to control light passing through the sensor. This will ensure a proper exposure. The shutter speed can vary from very fast to very slowly and is expressed in fractions. The aperture size inside the lens can vary from the smallest to the largest. These two variables (speed of shutter and aperture size) will control the exposure and light transmission.

Basics of Exposure Mods

There are several exposure modes that your camera offers, including ‘Program, Shutter Priority, Aperture Priority, Manual’. Let’s start with the Program Mode. The Program Mode is a mode that allows your camera to examine the scene and take into consideration brightness, contrast, color, etc. Your camera will perform these evaluations and also determine distance and focus, which will allow you to render an image with sharp detail. This all happens within a matter of seconds from the moment that you press the shutter button. This is truly a marvel of modern innovation!

The Shutter Priority Mode is the second mode that I will discuss. The shutter priority mode allows you to select the shutter speed and assign the aperture value to your camera’s computer, unlike the program mode where the camera’s computer analyzes the scene. This mode is useful for creative reasons, such as low-light situations or fast-moving action.

Let’s now look at the Aperture Priority Mode. The Aperture Priority Mode is similar to the shutter priority mode, in that both you and the computer play a role in creating the exposure. You can now choose the aperture value, and the shutter speed will be chosen by your camera’s software. You can control the depth-of-field by choosing aperture priority mode. Another reason to choose aperture priority mode is to reduce background blur, as in portraiture where you can have your subject in sharp focus and the background out of focus.

Last, but not least, is the Manual Mode. This mode is very different to the other three I’ve described. Manual mode gives you the opportunity to adjust both the shutter speed and the aperture value. These values directly affect not only the exposure, but also the appearance of the photograph.

Because your camera doesn’t appreciate creativity, I used the term “creative” in my paragraph. For a moment, let me get off my soapbox and say that both your DSLR and mine lack common sense. Let me explain. Your DSL does not show a charming bride and groom at a wedding. This is a common scene for wedding photographers and portrait photographers. The camera only sees the groom’s tuxedo and the bride’s dress in black against a background of various colors. Your creative preferences may not be reflected in the selections of aperture and shutter speed that your DSLR makes. The camera does exactly what it was designed to do: create a proper exposure.

There are many options for how to capture a scene. Although exposure is a major part of your job as a photographer there are many other ways to achieve it. Combining your exposure knowledge with creative use of shutter speed, aperture, and shutter speed will enable you to explore depths that are both rewarding as well as challenging in photography.