Ahhh! Sheila, don't be embarrassed.... when I went to college the first time around (1986) I had to take remedial math classes. So you're not the only one that has issues with numbers!

If you meter off the grey card you do not need to make any adjustments to your shutter speed. Because this is going to give you the correct exposure for mid tones, and your darker and lighter tones will fall into place properly. So you would:

1. meter off the grey card, setting it to what it tells you is the normal reading
2. compose your image
3. shoot

Now keep in mind that when I speak about making adjustments to your exposure this is only if you do not have a grey card and need to meter without one. You could change the shutter speed to let in more or less light, or change the aperture setting or even the ISO speed. They all work in conjunction with each other. Shutter speed was just the quickest way for me to show you when shooting the test samples.

To elaborate a bit more..... in the example of white.... if you were out on a snowy day and did not have a grey card with you, and you took a picture of this snowy scene, if you used your camera in Auto mode, or even just followed the meters advice in manual mode and set it to what the meter says is the normal exposure you would end up with a grey snow..... by changing the shutter speed or aperture to let in more light, you would be assuring yourself that the snow would look white in the final image.

As far as a pattern of numbers..... I agree that it may not always be so easy to see the pattern, and this is because the numbers are not always exactly doubled but close to it.... I'll see what I can do to make a STOPs guide that will help a bit more I think. But if you can multiply and divide by the number 2 that is all you need to know! I swear!!!

Now let me ask you a question..... does your camera measure stops in 1/3 or 1/2 increments? There should be a place in your manual that says this. And usually you can, in the camera settings change this..... I ask because the answer will tell me whether you do two clicks or three clicks to increase or decrease to the next stop.

Tom a white card is no good for measuring exposure.... that would be used for white balance which has to do with the color temperature of the light and how you want the camera to perceive and process it. White balance and exposure are two totally different things. White balance is comparable to film in that there are films made for daylight and films made for use with tungsten lighting.....

Message edited on: 03/18/2005 06:24

I am, therefore I create.......
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