For most of our photos, I used the Aperture Priority mode. This mode allows the photographer to set the desired aperture and lets the camera determine the correct shutter speed. The automatic shutter speed selection allows one to move faster and be more spontaneous. In addition, automatic metering works especially well outdoors on overcast days, as the scenes generally have lower contrast in this condition.

The 1/3 stop overexposure has made our photos slightly brighter overall, rendering our skin tone fairer. It can be set up using the Exposure Compensation function. For cameras that have coarser compensation settings of +1/2, +1, etc, select an overexposure of 1/2 stop.

Although automatic metering does a good job most of the time, I will play safe by taking a few more shots with different exposures if the scene is too contrasting. For a darker background, take a few more pictures with progressively more underexposure (eg, 0, -1/3, -2/3, -1 stop). For a lighter background, shoot with progressively more overexposure.

Using automatic metering with overexposure, as well as shooting with various exposures in more contrastingly lit conditions, I got consistently good results for our DIY wedding photos.

In the next section, I will share my experience in using the manual metering feature of any SLR cameras. The materials will be more technical. It is perfectly fine to skip forward, as you can handle most situations with the techniques already mentioned above.


More advanced metering techniques
Under very contrasting light conditions, however, automatic metering can make mistakes, resulting in photos with incorrect exposure.

Have you ever taken pictures on a ski slope or against a totally white background? If you were using automatic metering, your pictures would probably have turned out to be too dark. The snow white background would look gray and everything else (especially people's faces) would be underexposed. Why? This is because the light metering system in all cameras is calibrated to render the overall picture in the mid-tone — not too bright, not too dark. Since the majority of the picture is white in color, the camera proceeds to find an exposure that renders it in the mid-tone gray, and inadvertently makes other things too dark in the picture. This gray is sometimes called the "18% gray" — a technical term for the gray color that is midway between white and black.

In the manual mode, the photographer is expected to provide the camera with this reference color by pointing it towards something that is roughly 18% gray. How to find this spot? I can share three methods I am familiar with:

•	using a gray card — Accurate, but can be inconvenient.
•	using the face of the bride; then overexpose by 1-1/2 stops — This is the most convenient method for people pictures.
•	using objects that are equivalent to 18% gray — Do this when you don't have a gray card. I will share a new way to find these objects.

Using a gray card and the procedures for manual metering
The gray cards are painted exactly 18% gray. The short manuals that come with the gray cards can be a good reference. Here, I share how I used them:

I first switched to the manual metering mode and had Rain hold the card next to her face and faced it directly towards the camera. I filled the entire viewfinder with the gray card (you may have to get close to the card, as in the middle picture below). At this point, I adjusted the aperture and shutter speed until the camera indicated a 1/3 stop (or 1/2) overexposure (See last section). Next, I stepped back, composed the picture, and took the shot using the aperture and shutter settings I just selected.



The gist of this procedure is that I set the exposure while the light meter only saw the reference color (by filling the entire viewfinder with the card). I then kept this exposure setting when I took the picture.

If this process seems a bit involved, you can consider using exposure lock and spot metering. These functions are there to make metering easier.

Exposure Lock is used in conjunction with the Aperture and Shutter Priority modes. How to use it? For example, in Aperture Priority mode, you would first fill the entire viewfinder with the gray card, as in the middle picture above. Select the desired aperture and let the camera determine the shutter setting. At this point, lock the exposure (please refer to the manual of your camera). This function holds the aperture and shutter settings unchanged until you press the shutter button. Now, walk back to composite the picture and take it.

If your camera has the spot metering mode, it can be even easier. Spot metering means that the light meter will only take input from a very small spot in the viewfinder, neglecting the rest of the scene. Usually this is the 5% area at the center of the viewfinder. This is how I would use this mode in conjunction with exposure lock:

First switch to the spot metering mode. Instead of filling the entire viewfinder with the gray card, point and zoom towards it. Make sure that it covers the central area of the viewfinder before locking the exposure. Then, zoom back, compose, and shoot. Remember to hide the gray card of course!


Metering off the face of the bride

 
Similar to the technique with gray card, I first fill the viewfinder with the face of the subject and apply exposure compensation. This technique allowed me to get the right exposure for Rain's face in this severely backlit condition.

This actually is my favorite way to find an accurate exposure for outdoor portraits. It worked wonderfully for me in this trip. I used Rain's face as the reference color, instead of the 18% gray. But Rain's skin is much lighter than 18% gray, so I used the exposure compensation function to overexpose. This is how the theory goes: Overexposure renders the reference color lighter than 18% gray. When the Asian or Caucasian faces are used as the reference color, this is exactly what we need. From my experience, Rain's skin tone is rendered in the correct color with 1-1/3 stop overexposure compensation.

Different people have different skin tones. So you may need do some experiments to find out the right formula for you. For example, I can imagine much less or no compensation is needed for the tanned or darker skin. However, the exact value will depend on the subject and the overall lighting condition. So, try a wide range of compensation in different lighting conditions, see the results and determine what kind of exposure compensation you need.

So far, I find this technique delivers the best result, as the bride's face is the one spot in the picture that is consistent all the time.


Finding 18% gray in this colorful world
Metering off a gray card is accurate, but can be cumbersome. Sometimes, one just does not have a gray card handy. In those occasions, I would find some gray-equivalent spots in the scene instead. However, we are not in a black and white world. What can we do? We have a great tool in Photoshop, or any drawing software. This is how I taught myself to see 18% gray in this colorful world:

First, find color pictures that are correctly exposed (those that look fine to you) and change them to black and white in Photoshop (menu: Image -> Mode -> Grayscale). Next, define a gray color that has a 128 value in all red, green and blue colors. This is mid-tone gray corresponds to roughly 18% gray. Draw a small circle with this gray and move it around your now black-and-white pictures to find a spot where this gray color matches the immediate surroundings. Then, check what color the surroundings is in from the original color picture:

The patch of grass just behind Rain is roughly 18% gray. Compare it with the color picture. See how it "feels" in color. This is a way to develop your intuition for the 18% gray in the colorful world.

The asphalt sidewalk is pretty much 18% gray.

A pure red surface under soft light is also close to 18% gray.

From my experience, these are good references for 18% gray when the light is soft: surfaces red in color, patches of grass, the asphalt pavement right underneath your feet, and the clear blue sky. However, it may vary depending on one's photography style, so you may need to find our your own references.

Once the patch of 18% gray is found, treat it like the gray card, meter off this spot, lock the exposure, then compose and shoot.


Books on exposure
The above are my experience with exposure. You can always find your own creative ways or learn from other people's experiences on this subject. Here are two books from which I have gained extensive knowledge on exposure: