Manipulating Light in Recording

Here's some follow-up on metering that to me makes mastering exposure worthwhile.
Moving light values around—it’s an odd idea, but one that allows you to make creative choices about how light is recorded. You can work to get as much visual information and tonal richness as possible, or you can eliminate certain values for graphic effects. Though it's usually best to go for the former, the ability to juggle recorded tonal values is a key creative element in photography that brings a personal touch to an often forgotten skill—seeing and interpreting light as you shoot.
One of the ways to begin the process is to shun the “matrix” or “evaluative” metering pattern. Not that there’s anything incorrect or faulty with that pattern; it’s just that we want to be able to direct the exposure system to read values as middle gray. Move on over to spot metering pattern.
If you spot meter off a bright area in a tonally-varied scene and do nothing, the bright areas will record as middle gray and the darker areas will be compressed down into darker and darker tones. Conversely, if you meter and expose for the darkest area in the scene the brighter areas record brighter on film and may be driven up into overexposure. Think of the tonal scale as working in lock step, with the ability to record a range of values as having a fixed spread that can be moved up and down the grayscale “spectrum” of brightness values.
Once this idea becomes real to you the path toward being able to manipulate light should open. You can, as mentioned, read only from a bright value and record that as middle gray, and have the darker areas lose detail and become dark tones. Or, you can read the bright value as middle gray and then compensate exposure by opening up two stops; thus the birghter value will record as bright with texture and visual information. Or, you can open up three stops and have that value record as bright, textureless tone. (For example, plus two would keep the texture of wood in a brightly lit white picket fence; plus three would give you pure, driven snow.)
Conversely, you can read the significant shadow value and have it record as middle gray, which will make the brighter values record brighter still (or perhaps become overexposed.) You can also read the dark value as middle gray, close down two stops to have detail recorded in that dark value. Or, or you can use that same reading, close down three stops and just get a deep tone with virtually no visual information. In these ways you control what is recorded with detail, and what records as dark or bright tones without detail. Compensation is not limited to working with two stops--you can manipulate values by one stop, or by half stops if that serves your purposes.
The above assumes you are working in an autoexposure mode, like aperture priority. If you prefer working in manual so much the better, as you can dispense with using the exposure compensation and exposure lock features on your camera.
All this gives you control over highlights and shadows, and how the scene you have in front of you will record. Once you grasp the concept of value and tonal manipulation you have a wide range of choices that allow you to shape the exposure in many ways.

Spot metering for the highlight in this shot "drives down" the darker values into deep shadow, or pure tone.

Image and text copyright: George Schaub

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Digital Image Quality Considerations

Today’s digital cameras range from simple point and shoot models to those used by pros. One of the keys to getting good images to print is the megapixel count of the sensor. Mega means “millions” and refers to the number of photo sites—or light and image gathering points—on the sensor. If you would like to make prints as large as 8 x 10 inches you will need at least a 6-megapixel camera. If you want to make larger prints—or get the best quality in your 8 x 10 inch prints—then a higher megapixel camera is recommended.

You might think that you can simply buy an older camera and get the megapixel count required to make great images and prints, but the key here is in the image processor. Older digital cameras tend to produce much noisier images with numerous image “artifacts” that can be quite detrimental to image quality. My advice is to avoid buying a used digital camera made prior to 2009.


You have a number of options when making photographs with your digital camera. For the best prints follow these guidelines:
If you have a camera that only allows you to photograph in JPEG format:
1) Choose the largest file size you can get. If you have a choice of various pixel resolutions choose the largest. This is generally indicated as “L” on the menu choice (with M or medium and B or basic also available.)
2) Choose the lowest compression ratio. Compression is a way for the system to gather more images on a given capacity memory card, but it tosses away information when it writes to the card and replaces that information with mathematical formulas, not “raw” image data. If, for example, you have a choice between Super Fine, Fine and Normal, or some such naming scheme, choose Super Fine.
3) Don’t “tweak” the image processor in the camera with contrast or sharpness settings. These are fine for special effects in the camera, but we can do better with the image information later in the digital darkroom.
4) Don’t use digital zoom. This actually crops into the sensor rather than getting optical information through the lens. Even if you use the largest available resolution (Large) and lowest compression you’ll lose information.

If you have a camera that allows you to choose between JPEG and Raw format, do the following:
1) Choose Raw. The only drawback to Raw is that you have to open and view and change the image file in special software, usually bundled with the camera that has a Raw mode option.
2) If you have a choice of pixel resolutions in Raw choose the highest pixel count.

Although the image resolution or file size is key when making prints, that’s just part of the equation. Exposure and lens sharpness and how the camera’s internal image processor converts the data from the sensor to digitized image information have a very important role to play as well.

When thinking about settings on your digital camera consider how file format and compression will affect results, and what the end use of the image will be. This shot was made in a coastal town in Maine using RAW file format on a Canon DSLR.

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Copyright: George Schaub 2011