Zone metering?

Question

Does anyone know how to meter a shot by zones and then calculate, so that every zone you can manipulate it and expose it as you want...all in just one shot. It`s a very hard procedure. Tnx

i use a digital Canon 30D and

Answer 1

It may be the way I am reading your question, but you can't meter and expose zones individually. The zone system is called a system for a reason and also includes the developement and printing for film and the equivalent for digital. The exposure is only one part.

You can meter almost anything and put it in any zone you want through your choice of exposure, but all tones in the image will shift in the same direction and to the same degree. The dynamic range of the film or sensor, because they can only respond to a limited range, will determine where you lose detail in both the highs an lows.

This is hard for many non photographers and some photographers to understand, so I made a graphic to play with that I think illustrates what's going on. You can download it at:

http://picasaweb.google.com/Vance.Lear/GrayScaleZoneVisualizer/photo?authkey=aqSTu_nagwU#5124260148610513490

Cut out the top gray scale and use it to slide back and forth on the lower, larger continous scale. The white points on each are middle gray.

If you align the white points, you have what you would get if your exposure was set by a gray card. You can see that the sensor/film drops off at either end. This represents the recording limits of the film/sensor.

There is no detail in either the white or black part of the slider.

Let's say that somewhere past the end of the slider on the larger scale is a subject of interest in the brighter part that you want to hold some detail in. Not much, but some. Move the slider to the point where the gray just before the white covers that area. This represents metering for and assigning like a zone 7 to that, but take a look at what happens to how the sensor treats the rest of the scale. The details in the darker part of the scale will get lost because they have now been dropped to black.

Metering and setting your exposure is how you slide up and down the larger scale. You can also move the scale down and watch how things will blow out in the highlights. As you can see, everythng changes as a block and you can't put individual parts in assigned zones independently of the exposure. These types of choices, what you put where in terms of tone, are the ones you have to make. It's kind of a motto of mine that 'the correct exposure may not be the right exposure.'

Anyway, play with it and see if it helps understand what's going on regarding zones and exposure.

Vance

Addendum:

I would take wacky's advice and use his reference and use the slider graphic to understand it visually.

Answer 2

I can only give you an outline.

With an expensive digital camera I recommend just use the histogram.

The zone method was invented for use with conventional photography, especially with negative film.
About 8 zones are possible with negative film, 5 with slides and about 5 with a digital camera.
Zone 0 is the deepest tone in the picture. Mid tone should be got from a 18% greyscale card, or from a chessboard pattern of black and white that you print yourself.
Zone 7 is the brightest thing in the picture that you wish to capture with some detail.

Anything brighter or darker than this will not be capture on the negative.

Each zone corresponds to a doubling of light, and 2^8 = 256, so you have a range of about 256 to 1 to experiment with.

Answer 3

Well you are talking about the zone system, but what you haven't clarified is if you are using film or shooting digital. As the previous person mentioned, you have limits as to how many zones you will be able to capture. What I mean by this is that you are not going to be able to get detail in the lightest zone, and the darkest zone all in one negative/image.
It would be quite lengthy to tell you how to meter your image, and without examples it would be hard for you to visualize what I am talking about. I would suggest you read the simplified zone system http://www.simplifiedzonesystem.com/