TPB Staff
01-11-2009, 02:28 PM
Exposure accuracy can be greatly improved by taking a reading from an area within the scene that is of middle value – or, in other words, an area or surface within the scene that is midway between the lightest and the darkest tonal values of the main subject.
When determining tonal values, it is important to remember that the meter – either hand-held or within the camera – assumes that whatever surface it reads is a middle, or average, tonal value. Therefore, a reading taken from any uniform surface, used to determine your exposure, will give you exposure settings that are meant to reproduce that surface as a middle gray in your final image.
Keep this fact in mind as well: light meters are calibrated to reproduce values of middle gray.
How to Use the Gray Card:
Gray cards are inexpensive and can be especially useful in obtaining an average reading from the light falling onto the subject. They can be used with hand held meters as well as through the lens.
Position the gray card so that it is in the same light as your subject, and make sure the gray side of the card is facing the spot you will be shooting from. Take care to angle the card so that there is no glare when you aim your hand held meter or your camera at it.
With a hand held light meter: after positioning the gray card as above, point the meter directly at the card, and take the meter reading.
When metering through the lens on your camera: Make sure your camera is on manual mode. Pointing your camera at the gray card, zoom your lens until you have completely filled the frame with the gray card. Aim your camera so that all you see in the viewfinder is the gray card.
While holding the lens steady on the gray card, adjust your aperture and shutter speed settings until the camera meter indicates a correct exposure setting. Make a note of your aperture and shutter speed.
At this point, from either method, you may adjust the aperture and corresponding shutter speed as needed to obtain the effect you want. For instance, you may want to change the aperture for depth of field purposes. Remember that if you adjust one, you’ll need to adjust the other to make an equivalent exposure.
Compose, focus and shoot.
When determining tonal values, it is important to remember that the meter – either hand-held or within the camera – assumes that whatever surface it reads is a middle, or average, tonal value. Therefore, a reading taken from any uniform surface, used to determine your exposure, will give you exposure settings that are meant to reproduce that surface as a middle gray in your final image.
Keep this fact in mind as well: light meters are calibrated to reproduce values of middle gray.
How to Use the Gray Card:
Gray cards are inexpensive and can be especially useful in obtaining an average reading from the light falling onto the subject. They can be used with hand held meters as well as through the lens.
Position the gray card so that it is in the same light as your subject, and make sure the gray side of the card is facing the spot you will be shooting from. Take care to angle the card so that there is no glare when you aim your hand held meter or your camera at it.
With a hand held light meter: after positioning the gray card as above, point the meter directly at the card, and take the meter reading.
When metering through the lens on your camera: Make sure your camera is on manual mode. Pointing your camera at the gray card, zoom your lens until you have completely filled the frame with the gray card. Aim your camera so that all you see in the viewfinder is the gray card.
While holding the lens steady on the gray card, adjust your aperture and shutter speed settings until the camera meter indicates a correct exposure setting. Make a note of your aperture and shutter speed.
At this point, from either method, you may adjust the aperture and corresponding shutter speed as needed to obtain the effect you want. For instance, you may want to change the aperture for depth of field purposes. Remember that if you adjust one, you’ll need to adjust the other to make an equivalent exposure.
Compose, focus and shoot.