When you start diving into advanced areas of a subject without a proper understanding of the basics, ideas will often seem complicated and learning will feel forced. It's like starting a movie halfway through and trying to piece together what probably happened in the beginning to be able to make sense of what's happening now. Understanding the basic concept of how a camera works will provide the foundation needed for the learning of the techniques in this course to come naturally.

Let’s start with a film camera as an example. A film camera has a strip of film inside that reacts differently to different colors and intensities of light. Exposure to light for only a small fraction of a second will create a chemical change in the film that stores an image. You can think of the light very gently burning the film to create this impression. You can choose to use extra sensitive film for shooting in low light, or less sensitive film for shooting during the day. The film is located behind the shutter. The shutter opens for an adjustable period of time to allow light to pass onto the film and then shuts. The longer the shutter is open, the more light is let onto the film. Below are two unedited photos of a living room with the lights off, the camera settings for each were the same except for the shutter speed.

With a digital camera, we replace the film with a sensor. The sensitivity of the sensor can be easily adjusted for different lighting environments. The name that tracks the sensitivity of the sensor is called the ISO.

The aperture is the size of the opening inside of the lens. Adjust the aperture to be wider and you will let more light through. The size of the aperture also affects the depth of the area that’s in focus. Below you can see how the aperture can be adjusted to let more or less light in.

By setting the shutter speed, ISO, and aperture, you are controlling how bright or dark your photo will be. These three settings are at the top of the camera display below. 1/200 for shutter speed, F2.8 for aperture, and ISO 400 for the sensor. Below those numbers you see a scale with a zero in the middle and negative numbers to the left, and positive numbers to the right. This is your exposure value or EV. Zero is an even exposure, negative numbers are darker, and positive is brighter. We can change the EV of our scene by adjusting either or all of the three settings.

One of the biggest tests of any camera and also why a camera is expensive is how well it performs in low light at a high ISO. Say you were shooting a crowd at night. The crowd is moving so the shutter speed can’t be too long or you will get blur. The aperture can’t be too wide or they won’t all be in focus. This leaves you having to crank up the ISO. A smaller, less expensive sensor will likely have more noise and image degradation at a high ISO compared to a high end camera. Look at the grain in the image below which was shot at a high ISO on an entry level camera.

This brings us to the advantage that Real Estate Photography offers when choosing a camera. We can almost always have the ISO at the lowest setting, giving us the best image the camera is capable of producing, every time. This is because even in a poorly lit room we can simply decrease the shutter speed as long as we need. It can be open for a full minute because the house isn’t moving and we have the camera on a tripod. With this in mind we'll explore options for your first camera in the next section, as well as why an inexpensive camera is actually an advantage when it comes to editing.