Understanding the manual mode of the camera and adjusting controls while photographing people, or composing a landscape, can seem overwhelming for new photographers. Even experienced shooters who have relied on the automated modes can be intimidated by attempts to shoot in manual mode. By not using manual mode, photographers limit the control over their images and the predictability of their results. Shooting in manual mode allows us to have complete control over our photographs so we can get the results we have in mind when we’re shooting. Following are the main terms and concepts of shooting in manual mode.
Camera Terms and Concepts
Exposure The amount of light that is captured by the camera’s sensor resulting in the brightness of the recorded image.
ISO Controls the sensitivity of the camera to light. Low ISO numbers make the camera less sensitive to light and are generally used in brighter lighting conditions. High ISO numbers may be needed to take photos when light levels are low.
Shutter Speed Determines the length of time the shutter is open and light is allowed to enter the camera.
Aperture An opening in the lens through which light enters when the shutter button is pressed. It’s like the size of the window.
F Stop A number that represents the size of the aperture.
White Balance adjusts the camera’s sensitivity to specific colors to compensate for color casts in a scene. The result is that color casts are neutralized so the subject’s colors look more accurate.
Depth of Field The Range of reasonably sharp focus within a scene, from the closest point to the camera that is within reasonably sharp focus, to the furthest point from the camera that is in reasonably sharp focus.
Histogram A representation of the tones of a scene, and the number of pixels per tone, in the form of a graph
IF you have ever photographed a scene that was primarily all white, like a snow scene or a beach scene with lots of sand, the chances are good that your snow scene came out darker than you thought it should. Sound familiar? Likewise, you may have taken a nice close up photo of your black dog with the camera on an automatic mode. In this case the picture came out lighter than you would have expected it to. You ended up with a gray dog instead of black. The reason for this is that cameras are designed to reproduce any scene they are pointed at as an average and typical scene.
If the scene were a single tone, regardless of how light or dark that single tone is, the camera will give a correct exposure to display it as a middle tone gray. The camera measures the amount of light reflecting off of a scene, and determines how much of that light is needed to reproduce the scene or object as an average scene. It then adjusts the shutter speed, aperture, and/or ISO, to record only that amount of light. The value given to this average scene is 18% gray.
The answer to this problem is to make sure that the camera is actually exposing for an average scene. ( At this time, we are only considering the tone, or how light or dark the scene is, not the color.) One way to do that is to use a “gray card.” Several manufacturers make a gray card for the purposes of determining exposure. This gray card has the 18% brightness value that the camera’s light meter interprets a scene to be. By placing the gray card in the same light that we want to expose for in our scene, we can use the camera’s spot metering mode to measure the light reflecting off of the card to determine the correct exposure. This should be a very accurate exposure if you placed the card in the right light for how you want to expose the scene.
It is not usually necessary to use a gray card however, as finding an area of the scene that is about halfway between white and black, and in the light you want to expose for, will do the job. Also, with digital cameras, we can now check the exposure of a scene buy using the histogram.
But we will talk about the histogram a little later.