Even with the most advanced autofocus (AF) system there are times when it just can’t get the subject sharp or when its better to focus manually.
With macro photography, for example, many camera seem determined to focus much further away than the subject, so it’s best to turn off the AF system and do the job yourself.
Autofocus systems can also struggle when there are objects between the camera and the subject, foreground vegetation can be a real problem in wildlife photography for instance.
In principle, manual focusing is simple. You just look through the viewfinder and rotate the focus ring until the subject is sharp. But it can actually be quite hard to get a clear view of your subject and to ensure that exactly the right part is sharp.
Small focusing errors can sometimes be tolerated if you’re shooting with small apertures to capture lots of depth of field, but precision is vital at wide apertures.
Thankfully a few recent advances in technology can make accurate manual focusing a bit easier than it used to be.
While traditionalist may have originally scoffed at the benefit of composing images on a digital camera’s screen rather than in a viewfinder, many have now come to realise that there are some significant advantages when you’re focusing manually in many situations.
When the camera is mounted on a tripod so it can’t wobble about and the subject is motionless, for instance, it makes sense to compose the image on a camera’s rear screen because it’s significantly larger than the viewfinder, thus giving a clearer view.
It’s also possible to magnify sections of the scene so you get a really clear view of small details and you can make sure that they’re perfectly sharp.
In many cases you can even shift the magnified section around so that you can check the whole scene’s sharpness and depth of field. It enables a level of accuracy that just isn’t possible looking through a traditional viewfinder.
Another great thing about focusing when using Live View is that you’re looking at the image formed on the image sensor itself. This means it avoids any front or back focusing issues where the subject looks sharp in the viewfinder but is actually a little out of focus in the image.
The screen on the back of compact system cameras automatically operate in Live View mode, but this mode needs to be activated with SLRs as they are designed with viewfinder use in mind.
With the exception of the Fuji X-Pro 1 and X-E2 which have hybrid viewfinders, the viewfinders found in compact system cameras are electronic. Electronic viewfinders (EVF) use the Live View feed from a camera’s imaging sensor to create an image in a small screen in the viewfinder.
The first EVFs were found in digital bridge cameras (compact cameras with fixed zoom lenses and SLR-like design) and they were pretty sorry affairs. The image was noisy, lacked dynamic range and was a poor colour match for both the scene and the captured image.
Happily things have improved enormously and the EVFs in modern compact system cameras give a very clear view of the scene, with plenty of detail.
Like the Live View image on the main screen of an SLR or compact system camera, it’s also possible to enlarge a section of the scene to allow precise manual focusing. In most cases this magnification can be set to occur as soon as the focus is adjusted.
In some cases the enlarged view can be shown overlaying the whole scene so you have a rough idea of composition when focusing manually. Fujifilm, however, has taken things a step further with the Fuji X-T1 by allowing a whole scene to be seen alongside the enlarged view. This is made possible by the large size of the X-T1’s viewfinder.
Many cameras now feature something called focus peaking. This started life in video cameras and it highlights the areas of highest contrast, which are usually the areas of sharpest focus.
It can be used when focusing manually with some SLRs in Live View mode and on many compact system cameras.
When focus peaking is activated the sharpest areas are highlighted in a colour, which can often be selected by the photographer – red is a good option because it stands out well in many scenes.
Focus peaking is especially useful when shooting video because it allows you see very easily which areas of a scene are in sharp focus and to see where the focus is shifted to as a lens manual focus ring is rotated. It can also be very helpful for stills photography and can often be used at the same time a selective magnification.