Rudy Winston
Rudy Winston

Rudy Winston has over 17 years experience with Canon USA's Pro Products team, and has been responsible during that time for training Canon's staff on new products, creating presentations for customers and dealers, numerous writing projects, and providing technical assistance to professional and amateur photographers.

Slow down and create with Spot metering

April 08, 2014

I’ll be the first to admit that most of the time, I shoot still images using an auto exposure mode (usually Av), and extensively use Evaluative metering. It mostly works well and is easily fine-tuned using Exposure Compensation. The Quick Control Dial on the back of mid-range and high-end EOS HDSLR cameras is ideally positioned to make these adjustments almost seamlessly. For a long time, I’ve felt that photographers who are good with exposure control are good at applying exposure compensation.

But as effective as auto exposure is in today’s cameras, there are times when it really becomes satisfying to turn the clock back a bit, so to speak, and force myself to take more time and create each picture, not just “take” it. One way to do this is to set the camera to Spot metering and to switch over to Manual exposure mode.

Doing this certainly means you have to think about each shot you take. By definition, Spot metering reads only approximately 3% of your entire picture area. With meter readings so selective, you are obligated to select not only the “subject” you want to meter off of, but usually the part of the subject you want to initially meter from. And, most importantly, it’s imperative to understand how to compensate and deliberately over- or under-expose when you choose to meter from something that’s lighter or darker than a middle shade of gray would be.

It’s one thing to come across a scene with tricky lighting and momentarily switch from Evaluative to Spot metering — many photographers do it when the situation arises. But it’s another to force yourself to slow down and commit to using Spot metering for an entire morning, afternoon, or even whole day. It changes your entire approach to shooting. If metering and exposure control aren’t something you’re completely confident in, it’s a terrific way to really learn about how a camera’s meter reacts to light. And if you are good at exposure control, it’s a great way to force yourself to slow down from our usual frenzied 21st century pace, and think more carefully about each photograph we’re about to take.

But first, why Manual exposure mode?

It’s not that it’s inherently “better” than an auto mode. But once you place your exposure at a certain level, using Spot metering, Manual mode simplifies the task of keeping the exposure at that level. Confirmed users of Av, Tv, or P modes can certainly use AE Lock — I wrote a recent blog article about how useful the new AE Lock with Hold feature is — but with Manual, your settings simply won’t change until you physically move the Main Dial or the Quick Control Dial. It’s easy, therefore, to shoot multiple pictures of a given scene you’ve Spot metered — whether it’s a couple of shots or dozens.

Selectively metering just one part of a scene

This is maybe the most obvious reason to consider Spot metering. And, it’s perhaps the most common reason that we quickly switch from something like Evaluative to Spot for that occasional picture. A scene like this late afternoon statue, below, lit by a small shaft of sunlight is a perfect example.

With the central Spot metering area placed momentarily upon the sun-lit statue at the right of the frame, exposure is read, the camera set, and we re-compose and take several shots. The darker shadow areas of the scene don’t impact the exposure level and they’re recorded as deep, moody shadow tones.

Photo by Rudy Winston

 

The same is true in this image of a bright banner in a memorial park in Japan. Again, late afternoon sun highlighted just one part of the scene and Spot metering was ideal to measure that sunlight, and let the rest of the scene go dark — but still preserve enough shadow detail for it to be recognizable.

Photo by Rudy Winston

 

It probably goes without saying: when one part of a scene really captures your eye, Spot metering can be a very effective way of ensuring that it’s exposed as you want, without influence from other areas of the scene that are lit differently.

The next step: getting the exposure level you want

Anyone who’s used Spot metering very much knows that this is the spooky music playing in the background and is probably what keeps many users from really getting to know exposure control via Spot metering. What happens is simple: the shooter takes a Spot meter reading off a subject, sets exposure to what the meter says is correct (or in an auto exposure mode, locks it in place with AE Lock), and takes a shot — and it comes out excessively light or dark. Even the subject they carefully spot metered isn’t right. Many throw up their hands in frustration and revert to a full-area metering mode like Evaluative.

Spot metering with the camera is really no different from any other form of in-camera metering. It’s reflected-light metering, measuring not the amount of light falling onto your subject, but the amount of light reflecting off of it and toward the camera position. And, of course, different types of subjects will reflect different amounts of light, even when the amount of sunlight or artificial light hitting them is constant.

An obvious example is a bride and groom in their traditional black tux and white wedding dress. Take a Spot meter reading from the groom’s tux and then one from the bride’s white dress, and you’ll get radically different exposure recommendations. The white surface of the dress is far more reflective than the black tux, even if they’re standing next to each other, and the same light is hitting them. What to do? Record both readings and split the difference, setting shutter speed and/or lens aperture in between the two extremes?

Different photographers have different answers to this dilemma. Mine is simple:

  • Meter off of a part of the scene or subject that you know will be close to a neutral brightness tone — something that, if you were shooting black & white, would be properly reproduced as a middle shade of gray
  • Or deliberately change exposure for the light or dark parts of a scene that you Spot meter from

Some scenes make it easy, such as the one below. Green grass is perhaps Mother Nature’s way to give photographers a ready-made Gray Card. It reproduces as very close to a traditional 18% middle shade of gray and is a subject you can reliably meter from, set the camera to the meter-recommended settings, and take a shot — and expect results that usually are pretty close.

Here, we wanted the shadows on the gravestones to be dark and moody. An easy way to get that effect is simply to ignore them when metering — switch to Spot metering, read from the grass surface surrounding the gravestones, set the camera so the metering scale in the viewfinder shows a “proper” exposure level, and take as many shots as we want.

The key is that the green grass pretty much lets us expose as indicated in-camera, without much if any need to adjust anything further. But that’s not always going to be the case.

Photo by Rudy Winston

 

Recognizing a tone or color, and adjusting exposure accordingly

Here’s the heart of making Spot metering work, in any situation. The LCD image playback and histogram display on today’s DSLRs are a huge benefit here, making it easy to see when corrections are needed after the first shot. But with a little experience, you can gain the confidence to make these settings and put things pretty much where you want or need them to be, even before the first shot is taken.

“Placing” a light-colored tone, anything from a Caucasian skin tone to freshly fallen white snow, so that it’s rendered as the eye sees it can be done in the camera. And the more you practice it, the more control you’ll have over it.

The key point is this: if you Spot meter off of a known, light-colored object or part of a scene, and adjust exposure so that the object is rendered properly, nearly all other tones and subjects in the same scene will fall neatly into place and be rendered properly as well. So on that snow-covered field, if a landscape shooter took a Spot reading off the snow, deliberately adjusted his or her Manual exposure to intentionally over-expose that white tone and have it appear in the next image as a proper shade of white (with detail and texture), all other tones — the green of evergreen trees, the blue of the sky, the dark gray of an asphalt road that may cut across the scene, and so on — will all reproduce properly, too. You don’t have to take multiple Spot readings from those different parts of the scene. Just take one, predict how light or dark it’s likely to be, adjust exposure to render it properly, and take the shot!

A relatively easy one is a Caucasian skin tone. Everyone’s skin tones are slightly different, so there’s no one completely “correct” number here. But in general, Caucasian skin tones on people who aren’t deeply tanned will usually be lighter than a typical middle shade of gray. To Spot meter them properly, the overall final exposure needs to be adjusted slightly so that they are rendered lighter than that middle shade of “gray.”

How much? Again, there’s no one exact answer. But in general, adding +2/3 of a stop for a person with a typical Caucasian complexion, and perhaps +1 stop for a person with a lighter complexion, will put you solidly in-place for a good exposure. And again, get the face correctly exposed and the rest of the scene will usually fall right into place, too. In this shot, a Spot meter reading right off the cheek, deliberately over-exposed by 2/3 of a stop, was just what was needed for a clean exposure.

Photo by Rudy Winston

 

What about subjects with darker complexions? For a deeply tanned person, you may need no compensation; for a subject with a darker complexion, you may in fact need to under-expose the Spot metered tone for their skin tones to be accurately rendered.

Photo by Rudy Winston

 

This gorilla obviously isn’t a person, but we know his or her skin tone is in fact a very dark gray, close to black… a Spot reading on the cheek, just above the gray “beard,” was then adjusted to display minus 1.3 stops, rendering the animal’s skin a similar dark tone to how it appeared to the naked eye — but still preserving detail and texture.

Photo by Rudy Winston
Spot metering of white tones

This can sometimes be one of the most effective ways to use Spot metering. If something in the scene is a white or near-white color, you can effectively render it a true white in the final image if you Spot meter off it, and then deliberately over-expose by anywhere from 1.7 to 3 stops.

Photo by Rudy Winston

 

How much? It’ll depend on the subject itself and the way it’s lit, and even to some degree the camera you’re using. Freshly fallen snow on an overcast day may need a different adjustment than the same scene later, when the skies have cleared and it’s under sunlight. Practice, along with checking your histograms to make sure important white tones are not butting against the far right-side of the graph, will go a long way toward making this a smooth and predictable task for the critical photographer.

One of the keys is not simply “over-exposing” a white area, but rendering it as a true white tone in a final picture that preserves actual detail and texture in the subject. Below, a Spot reading off an upper portion of this orchid, deliberately over-exposed 2.3 stops, preserved some of the texture in the petals, without making it look a muddy gray.

Photo by Rudy Winston

 

Deliberate “wrong” exposure and Spot metering

Experienced shooters probably know where I’m going here. Up to now, we’ve been talking about Spot metering as a tool to let us selectively measure one part of a scene or subject, and carefully record it so that it appears close to “accurate” in our finished image.

But exposure can be a great creative tool, too. Intentionally under- or over-exposing an entire scene can sometimes change the meaning of the picture. And Spot metering can be a useful tool to pull out of the toolbox here. In the example below, a properly rendered picture of this late-afternoon country road would be little more than a shot of a country road. But by dramatically under-exposing, the sun-lit telephone wires become a graphic element and a completely different picture is the result.

Photo by Rudy Winston

 

Even with the small area read by Spot metering in Canon EOS DSLRs, these fine telephone wires were far too small to be accurately metered with Spot metering. Instead, it was easier to take a Spot reading from the overall road area and, from there, deliberately under-expose it — forcing it to record as a black shadow area with little to zero visible detail. Manual mode, Spot metering, and intentional under-exposure by 2.7 stops from the camera-recommended meter reading of the shadows did the trick!

Tying it all together: a commitment to a day of Spot metering

This is a great occasional exercise and, as I said earlier, an excellent way to really get to understand metering and in-camera exposure control. With the camera in Manual exposure mode, you’re forced to slow down, think about what you’re metering, how it’s lit, how you want things rendered in each image, and the final camera settings to get you there. You become more connected to the metering indicators in your camera, and to the Spot metering circle in your viewfinder. And even if it’s something you only do once in a while, the lessons it teaches carry over to typical everyday shooting, even run-and-gun shooting in an auto exposure mode with Evaluative metering.

As I said previously, people who are good with exposure control are usually good — or better than good — at understanding Exposure Compensation, the hows and whys of varying a camera-recommended meter reading to get the results they want. As sophisticated as today’s digital cameras are, the best photographers know that their meter readings are often just a suggestion, a starting point. Spot metering underscores that, especially if you try working with it for an entire shooting session.

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