LanguagesFocus points: Wider focusing points
The EOS-1D, 1D Mark II, 1D Mark II N, 1D Mark III, 1Ds, 1Ds Mark II, 1Ds Mark III, 1V and EOS 3 cameras have a Custom Function that in effect increases the size of the focusing points. Custom Function 17 (Custom Function III-8 on the EOS-1D Mark III and 1Ds Mark III) does this by creating a cluster of focus points that are all active.
Custom Function 17-1 (or III-8-1)
The focusing point selection range expands by one point around the manually selected point. In other words, a group of seven active points is created.
Custom Function 17-2 (or III-8-2)
The size of the cluster will depend on the focal length of the lens and the focus mode selected. This means that if the focal length is shorter than 300mm and One-Shot is set, just a single focusing point is active (as in normal use). This is the same for AI Servo mode and slow-moving subjects. However, if the camera detects a fast-moving subject, it will create a cluster of seven active focusing points to help ensure correct focus. When using a focal length longer than 300mm, the camera will always create a cluster of seven active points in One-Shot AF mode and in AI Servo with a slow-moving subject. This cluster then increases to 13 active points when the camera detects a fast-moving subject.
Extra points
The EOS 5D has six additional invisible focus points around the central point. By setting Custom Function 17 to ‘1’, these become active in AI Servo mode to help when you are focusing on moving subjects in the centre of the viewfinder.
Interchangeable focusing screens
Some EOS models take interchangeable focusing screens. Some of the alternate screens do not show the focus point positions. However, the active focusing point will still show up in red when you partially press the shutter button. This is because the red display is projected onto the screen – it is not part of the screen.
How many points
This table shows which EOS cameras have multipoint focusing, together with the number of points.
| EOS-1D | 45 |
| EOS-1D Mark II | 45 |
| EOS-1D Mark II N | 45 |
| EOS-1D Mark III | 45 |
| EOS-1Ds | 45 |
| EOS-1Ds Mark II | 45 |
| EOS-1Ds Mark III | 45 |
| EOS 5D | 15 |
| EOS 10D | 7 |
| EOS 20D | 9 |
| EOS 20Da | 9 |
| EOS 30D | 9 |
| EOS 40D | 9 |
| EOS 300D | 7 |
| EOS 350D | 7 |
| EOS 400D | 9 |
| EOS D30 | 3 |
| EOS D60 | 3 |
| EOS D2000 | 5 |
| EOS DCS 1 | 5 |
| EOS DCS 3 | 5 |
Metering
The camera’s evaluative metering system is linked to the focusing points, so that the area covered by the active focusing point is the area that is correctly exposed. If your EOS camera has multiple focusing points – whether three or 45 – you can set it to select the active point automatically. Most of the time it does a very good job. Automatic focusing point selection works by making the quite reasonable assumption that the most important part of the subject is that nearest the camera – which holds true for most people’s photographs most of the time – so that’s what the camera focuses on.
Most EOS cameras with multipoint focusing also allow you to take control of focus point selection. If you are unsure about focusing, leave your EOS to select the focus point automatically for most of your photographs. However, you always need to be aware of which focus point is being selected by the camera, and be ready to step in and take control where necessary. That’s because there are times when the camera doesn’t focus where you want it to. This is usually when there is some foreground detail that isn’t the main subject, but the camera thinks it is. So whenever you’re taking a photograph, press the shutter part way to focus and see which focus point lights up. If it’s not the one you want, then switch to manual point selection or use Focus Lock.
Focus Lock
Some photographers don’t bother switching to manual focus point selection. Instead, they move the camera around until an active focus point appears over the part of the subject they wish to focus on. Then they hold the shutter button down part way to hold the focus setting while they recompose the image. This feature is called ‘Focus Lock’ and can be used when the camera is set to automatic or manual focus point selection.
If this scene has been shot using automatic focus point selection, the lens might have focused on the nearest elements of the image, putting the main building out of focus. For this picture, the centre focusing point was used, ensuring that the main building was in focus and leaving the other elements to look after themselves.
