Focus tips

The focus areas on your camera are the ones that light up in the viewfinder or LCD screen when you half press the shutter. But do several squares light up as in the the above shot of my kitchen, or just the one? If the former, this tip is for you! One of the biggest steps you can take in getting tack sharp photos is to start using single point auto focus to decide for yourself what should be in focus and to nail the shot. Looking at the above image, you can see that the focus squares are on the kitchen chair, the flowers on the table, and the flowers at the back. So which of those is going to be in sharp focus. Well who knows? Well actually it's usually the nearest object or the most prominent, but can you be sure? Using the auto area or grid grid focus system is a bit like throwing a handful of darts and hoping one of them hits the bullseye, even more so when shooting using a shallow depth of field. [do action="tl-linktocurriculum2"] [/do] When new photographers first start out, they tend to let the camera decide how to take the shot, but they soon discover that letting some anonymous engineer in Japan make decisions is probably not the best way to go (ok, the engineer may not come from Japan, but you get my meaning!). Quite often, the default setting on new cameras is Auto Area / Grid focusing and the camera uses multiple points to decide where to focus. To be honest, more often than not, the camera focuses on the correct subject, because the subject is nearest to [...]

Rather than allow your camera to choose it's own focus area using focus 'auto-area / grid area', you'll get far more consistent results if you just use one focus area that you have control over. But depending on your camera, you may not be able to get out of the auto area / grid area mode unless you first get out of the 'full auto-mode' and switch to Aperture Priority, Shutter Speed priority or the 'P' mode. Once you've done that you should have a focus area in the dead centre of your viewfinder or LCD screen, it normally lights up when you half press the shutter. But, just like in the above photo, what if your main subject is not in the centre, or you want to use the rule of thirds for a better composition? 'Focus and re-compose' to the rescue All you need do is place the focus square on your main subject, and half-press the shutter. That will lock the focus and exposure. Then, keeping the shutter half-pressed, re-compose so that your subject is now in the correct position in the frame. [do action="tl-linktocurriculum2"] [/do] Many photographers use the 'focus and re-compose' technique all of the time, it's very simple to do and generally very accurate. But it can fail under some circumstances, if you're shooting at wide apertures and have a very shallow depth-of-field, when you re-compose the subject may no longer be on the same plane of focus, and so will not be tack sharp. In that case, just use one of the camera dials to move the focus area square over the subject, like in the photo at the top of the [...]

Auto focus systems on most DSLRs work by sensing the difference in contrast between edges, even those that use Phase Detection Autofocus. But when there are no sharp edges or contrast, or when there is not enough light to detect the contrast, the lens's auto focus will keep searching for an edge and will not be able to focus, this known as 'hunting'. For example, if you try to focus on a cloudless sky or on a solid coloured wall with no contrasting edges, the camera won't be able to acquire automatic focus because of lack of contrasting edges. These sequence of photos were taken at Speakers Corner, Hyde Park in London, where on Sunday mornings anybody can literally get up on their 'Soup Boxes' and scream their opinions to the world! In the shot above, had I tried to focus on the plain area of the Muslim ladies' bhurka, the lens would not have been able to lock focus, so I intentionally set the focus square partly on her face, bhurka nd background and got an instant focus lock. Similarly in this shot I focused on the man's face, had I tried to focus on his jacket, I would have had a problem. Again, on his face [do action="tl-linktonatlightdoc"] [/do]

As explained in a previous focusing tip, an alternative to the 'focus and re-compose' method is to use one of the other camera focus areas instead of the centre one. Different cameras have varying number of focus areas and many cameras allow you to change the number of focus areas to be used, via the menu settings. There are many variations, and you'll have to consult the dreaded manual to learn about your own camera. Here's some variations. The problem with using the outer focus areas Notice from the main image of the family that the outer focus areas are represented by a vertical line, rather than a cross hair. This is because, depending on the camera, some or even all of the outer squares are not as powerful as the centre square and may have trouble focusing in low light or when there is not a great deal of contrast (again, check your manual to see whether your outer focus areas have the cross hairs). So, bear in mind that if you're having trouble locking in the focus using an outer focus area, it's sometimes worth switching to using the centre focus area. [do action="tl-linktocurriculum1"] [/do] In the above main image, using the centre area, without using 'focus and re-composing', probably wouldn't work because the square is directly over the mum's blouse which has no edge contrast. So I could have moved the focus point to the top area or I could have used the centre one and 'focus and re-composed'. I can't remember which method I used, but it's in focus so I obviously got it right!!