Ian Rolfe discusses the fine art â€“ and the absolute necessity â€“ of correct metering.
If youâ€™re content being a photographer who shoots average subjects in average light, then switch your camera to â€œProgramâ€ and read no further. If, on the other hand, magical light and beautifully toned pictures tingle your senses, then an understanding of your meter is essential.
From your cameraâ€™s perspective, metering is the process of measuring light that is reflected from your subject, then adjusting your aperture and/or shutter speeds accordingly. Your cameraâ€™s light meter is the tool used to measure this light and your brain is the means used to verify the adjustments. Donâ€™t use one without the other.
Light meters are fantastic tools, but understanding their limits is critical to great photography. Leave behind the mindset that says, â€œI donâ€™t want to understand why it works, I just want it to workâ€. There are many reasons why this is not a positive approach, the most important one being that while a modern camera will deliver accurate exposure, it may not be the best exposure. This is why high-end cameras now provide a variety of metering options that include multipattern, spot and centre weighted. Knowing when and how to use each metering system requires an understanding of how they work.
Single lens reflex (SLR) cameras use reflective meters that are calibrated to give an average reading. The camera reads light â€œreflectedâ€ from the subject and averages out the light reading for a middle-grey tone. This is all very fine for middletoned subjects, but what if you want to photograph white daisies or snow; or a black horse or a darkskinned person? How do you change the exposure from what the camera is telling you to a more accurate setting? This is where knowledge is indispensable.
It is important to remember that your meter does not know what itâ€™s pointed at, so it will render everything a middle tone. If, for instance, you want to take a picture of a yellow flower against a black background, your meter will expose the background lighter and will overexpose the flower. Try overexposing at least one stop from what your meter is telling you and the results will be more pleasing. If, on the other hand, you are metering a dark red flower, try underexposing one stop. This seems counter-intuitive, but itâ€™s the way your meter works. Here are some colour guidelines: White is two stops lighter than medium. Pink is one stop lighter – as are sky blue, yellow, lime green and lavender. Fire-engine red is medium, so is royal blue, orange, green, purple and gold. Maroon is one stop darker, so is forest green, dark orange and brown. Remember this: overexpose light toned scenes and underexpose darker toned scenes. To obtain the most from vivid and colourful autumn scenes, slightly underexposing your shots will result in rich saturation and breathtaking results.
With the various metering modes found on most good SLRs, there are some points to keep in mind. Matrix â€“ or multi-pattern â€“ metering works well on almost all medium-toned scenes and in particular larger scenes, because in most landscapes the tonalities will combine to medium. Centre metering is not much use at all compared to multi-patterned metering and thus lacks the precision of newer metering modes. Spot metering is excellent for more difficult situations, as the most important tonality in your shot will be the one you choose â€“ and thus the most accurate.
This is where hand-held meters can hold their own, because they usually read the â€œincidentâ€ light that directly hits the photosensitive cell â€“ that is, the light that is falling on the subject rather than the light that is reflected from it. The incident meter eliminates the need to consider the reflectivity of your subject and thus the need to compensate exposure for dark or light tones. But even these meters require input from the photographer and an understanding of their limitations. However, for most photographers using 35mm SLRs, the inbuilt spot metering found in later model cameras is very accurate and more than adequate for your general needs. A thorough understanding of metering, metering modes and their effect upon your images will yield its benefits in your work immediately.
After all, light is our tool. Understanding it is the key.
For further assistance on this subject, Ian Rolfe can be contacted at firstname.lastname@example.org