Autofocus points Focus Focus Focus

 

In our first blog, we explored the importance of holding the camera correctly to make sure that your images will be as sharp as possible. The first rule of photography is that your image must be razor sharp. The second rule is that there are no rules and you need to have the ability to creatively have parts or all of your image out of focus on purpose. The key here is total creative control.

Our next goal is to learn about focusing your lens or lenses.

To begin with, your picture quality can only as good as the quality of the lens you own.

But we will talk about lenses on another blog. Lenses are not just another piece of glass that you put on a camera body to capture your images. But let’s get back to the matter at hand, there are two ways to focus your lens:

  1. Manual focus
  2. Auto-focus

Manual Focus

By using your manual focus mode, you have total control of your area of focus. Indeed, for general use auto-focus maybe easier but there will be times you will need your manual focus mode. It may feel clumsy or finicky but in the long run, you will have occasions where this extra level of control will give you results you might not otherwise achieve.

Times to use your Manual focus

  1. Macro photography

Macro photography is a matter of specifics. There usually is very little depth of field and it is critical to have the exact point of focus.

    2.  Landscape

Much like macro photography, landscape photography is dependant on critical focus and judicious depth of field.

       3.  Crowded scenes

When you are focusing on scenes that are busy the autofocus has a difficult time choosing the point that is important to you.

       4.  Street photography

It’s faster, controllable, and reliable

Using your manual focus

We talked about the proper way to hold your camera in the first blog. Hold the camera in your right hand and place your left hand under your lens. This gives you the best stability. When you turn the focusing barrel of your lens to the right you are focusing items that are closer than your last image. When you turn the barrel to the left, you are focusing items that are farther away.

There are three main viewfinders for focusing; all Matte Fresnel, Split Image Matte type, microprism.

A.   Fresnel – basically you have a matte, roughly ground surface that when your image is in focus, it is sharp.

      B. Split Image – to get a sharp image you align the two sides of a sharp edge.

      C. Microprism – The screen has a bright center area and the focusing is done on the central microprism spot.

But none of this helps if your diopter is not properly adjusted.

Where do we start

  1. Your viewfinder diopter
    •  Most people don’t realize that you can and should adjust the diopter on your camera diopter. If you don’t have a diopter on your camera you can get an add-on viewfinder lens.
    • Why would you use and adjust your diopter? Because although your picture through the lens is focused when you look through your viewer it may be fuzzy because it is like reading the newspaper with the wrong prescription glasses.
    • To adjust your diopter there is a small wheel or slider next to your viewfinder that you can slide or turn one way or another and this adjustment should align the viewfinder with the lens so you can feel certain about your sharpness.
    • The easiest way to adjust your diopter is to put your camera on a tripod or the edge of a table for stability. Make sure what you are looking has lots of pattern with sharp edges. Using your auto-focus press your shutter release halfway to focus your camera. At this point your image should be sharp so now you look through the viewfinder and adjust the diopter so that the image looks sharp.
    • If your camera doesn’t have auto-focus what do you do? In fact, if you haven’t properly adjusted your diopter most of your pictures would have been out of focus. To make sure your diopter matches your eyesight is to set up your camera on a tripod or table as close to ten feet from your subject as possible. Look through your viewfinder and adjust your diopter so that your image is in focus.
    • Finally, it is easier to move your diopter out of its optimum setting than you think. Remember to check it often to make sure it is correctly adjusted.
  2. Choosing the best auto-focus focus mode.

A. Single shot auto-focus (AF-S). You point the middle of the camera at your subject and gently press the shutter release halfway. The reason is that we depress the shutter half way is that we are taking pictures with a computer. This computer analyses the amount of light there is on the scene, the colours, and the distance the subject is from the camera for a sharp picture. If your subject moves, you must refocus.

  • Thankfully, in all camera modes more advanced than ‘Auto’, you can select which AF points you want the camera to use (ie all of them, just some of them, or only a particular one). You’ll either have a dedicated AF Point selection button (most Canon’s do), or perhaps it’s inside your menu (most Nikons it’s under AF -> AF Area Mode) and honestly, for 95% of you photography, you’re far better off setting it to ONLY USE THE CENTRE AUTO FOCUS POINT (single-point AF, and set to be the middle point).
  • Suited for still subjects. When you press the shutter button halfway, the camera will focus only once. With evaluative metering, the exposure setting will be set at the same time focus is achieved. While you hold down the shutter button halfway, the focus will be locked. You can then recompose the shot if desired.
  • Autofocus continuous (AF-C). As it says in the title, continuous means that if the subject moves closer or farther away the camera keeps finding the optimum focus. It even works when you move one way or another.
  • This AF mode is for moving subjects when the focusing distance keeps changing. While you hold down the shutter button halfway, the subject will be focused continuously. The exposure is set at the moment the picture is taken. When the AF point selection is automatic, the camera first uses the center AF point to focus. During autofocusing, if the subject moves away from the center AF point, focus tracking continues as long as the subject is covered by another AF point.

                       Missing the focus point

Tracking focus

  1. Autofocus auto (mode select) (AF-A). With this choice, the camera chooses for you which option will be better in a certain situation. The challenge is that you might not notice when it changes the method.
    1. [AI Focus AF] switches the AF mode from [One-Shot AF] to [AI Servo AF] automatically if the still subject starts moving. After the subject is focused in the One-Shot AF mode, if the subject starts moving, the camera will detect the movement and change the AF mode automatically to AI Servo AF.

 

  1. Picking the best combination of focus point
    • Single center focusing point. If you want to make sure that a specific point of your photograph is crystal clear in focus this is the one for you. It allows you to control precisely everything that you want in focus. You can use a center focus point or read your specific camera’s manual to figure out how you can easily change which single point you want to use.

  •  Various multi-focusing points. The theory is that by using more focusing points you will get an overall better-quality photograph. Another element is that by having more points in play you will get better tracking. A very important feature when photographing a moving target.

The only challenge with this system is when there isn’t a lot of light. Your camera needs contrast to focus.

This is just an overview. There are many great in-depth articles and webpages discussing the above. And of course, check your camera manual or camera manufacturer website.

To your great shooting

Bob and Chuck