Metering Modes and DSLR Auto-focus modes explained

Understand different metering modes and Auto-focus modes of your camera and the application of it.

Please share the love 

Spot

Spot metering mode utilises a very small section of the image area to create a meter reading. The metering area is typically 1% to 5% of the total image area that you see in your viewfinder. It’s usually represented by a small circle and fixed directly in the centre of the viewfinder image.

Some camera models allow the ‘spot’ to be moved around within the frame from focus point to focus point.

Center weighted

The centre-weighted metering mode concentrates 60 to 80 percent of the metering sensitivity to the central 1/3 of the viewfinder. The camera then factors in the balance of the reading based on a feathered look at the remaining 2/3s of the viewfinder.

This mode operates under the assumption that you will most likely centre your subject in the viewfinder.

Center-weighted metering is helpful in some of the same situations that you would use spot-metering mode. But, it takes into account a bit more area.

Zone

Zone metering is often referred to as matrix, evaluative, multi-zone, honeycomb, or segmented depending on the camera manufacturer.

Zone metering mode breaks down the image in the viewfinder into sections. The number of sections depends on the camera model. Typically it would be no less than 5, but it could be as many as a 1000.

Zone metering mode is excellent under the following circumstances-

  • You want to work fast with minimal thought process on your part.
  • The light is changing quickly.
  • Your angle to the subject and lighting is changing quickly (such as wildlife).
  • The lighting and contrast are not extreme.
  • Zone metering is an excellent choice for many subjects.

Autofocus points

When you look through the viewfinder you see whatever your lens is aimed at, but on the viewfinder display you also see the camera’s focus points. Their exact appearance and arrangement will vary by camera manufacturer and model; there will also be some variation according to what AF mode you are using. Furthermore, the number of autofocus points you see will depend on how sophisticated the camera is. Entry level DSLRs, for instance, may have as few as 7 points, while higher-end DSLRs with considerably more complex focusing systems may have more than 150 autofocus points. There are a number of mirrorless cameras that boast upwards of 150 autofocus points.

Each AF point is one of two types: vertical type or cross-type. Autofocus sensors of the vertical variety detect differences in contrast only along the vertical axis of the area on which the AF point is placed. Cross-type AF sensors are more accurate because they detect differences in contrast along both the vertical axis and horizontal axis. Most cameras contain a mix of these two kinds of sensors. Basic DSLR models will typically feature one cross-type AF point as the centre point, with the remainder being the standard vertical type. As you work your way up the ladder of camera sophistication, the number of cross- type points increases as does the accuracy and responsiveness of the overall AF system.

Autofocus modes

Not only do digital cameras make focusing faster and more accurate than their analog predecessors, they also provide a great deal of AF customisation designed to be adaptable to the characteristics of the scene/subject you are shooting. Once you’ve learned the options that are available to you, you will be well on your way to new heights of photographic efficiency.

Single Shot AF – This is the mode you will want to use for stationary subjects such as portraits (people or animals), flowers, architecture, cars, or landscapes. By pressing the shutter button halfway, the camera will meter the shot and lock focus on the AF point that you choose, so long as the subject stays at that selected point. If the subject moves, focus will not be acquired and if you try to press the shutter button completely no shot will be taken.

Continuous/Servo AF – This mode works by using the AF point that you choose to continuously focus on a subject while you keep the shutter button pressed halfway. As you might have guessed, continuous AF is the perfect solution to focusing on moving subjects such as your kids running around the yard, birds in flight, or anything else that is on the move. You would also use this mode for the panning technique, in which you track the motion of a subject with your camera to convey a sense of movement.

Autofocus areas

To further refine the autofocusing process, your camera allows you to specify exactly how you want to use your selected AF point(s) within a given AF mode. Let’s take a look at the most commonly available AF areas.

Single Point AF Area – This AF area is pretty self- explanatory: the camera will use only one focus point, chosen by you, to achieve focus. This technique works best for stationary subjects.

Dynamic/Expansion AF Area – In this mode you choose one AF point, which the camera will use to acquire initial focus. If your subject moves, the camera will automatically use one of the surrounding AF points to track the subject and keep it in focus. Of course, you will need to move your camera along with the subject to keep it within the focusing area. This AF area is best when you want to keep focus on a specific point, but allow yourself some breathing room when tracking fast moving subjects such as birds in flight.

Spot AF Area – This mode uses the AF point of your choosing and incorporates a smaller, more concentrated point used to achieve precise focus on a very small portion of a subject. If you are doing macro photography, particularly with subjects that aren’t moving and exhibit tiny details, the spot AF area will help you get sharp focus.

Remember that different camera manufacturers will use different names for the various AF modes and areas, and not all features will be available on all cameras, so be sure to consult your camera’s user manual for specific details.

HOW YOU CAN SUPPORT
THE HUNTERS OF LIGHT

From just $2 a month as a Patreon, you are not only receiving additional content and services, you are helping us keep the dream alive and we want to reward you for believing in and supporting the Hunters of Light Initiative. Sign up  to our Patreon page and help us continue to provide inspiration and motivation fo our photography community.