Manual focus: what you need to know to get sharp images
How to set hyperfocal distance
Hyperfocal distance is the point you focus on for the maximum depth of field that includes infinity (the point beyond which everything in an image looks sharp, right through to the horizon– and this will change depending on the focal length of the lens).
When you focus at infinity, you’re actually wasting two-thirds of your potential depth of field! The in-focus area of an image is partly governed by the aperture of the lens, and we know that the narrower the aperture, the greater the depth of field (learn How to find your lens’ sweet spot).
However, the way this area of sharpness is distributed is one-third in front of the spot you focus on and two-thirds behind it. It stands to reason, therefore, that if you focus on the horizon, or anywhere beyond the infinity mark, you are wasting two-thirds of your sharp area.
In the days before autofocus, manual focus-only lenses stopped at infinity, so all you had to do, when photographing stars at night for example, was to wind the focus ring all the way to the left, or anticlockwise, to get sharp results. Modern AF zoom lenses actually go some way beyond infinity to allow the autofocus mechanism to hunt, so twist your focus ring all the way to the left – and shoot at a wide aperture – and there may be nothing in focus in your image at all!
For a given aperture and focal length, look up the distance in the chart above and focus on an object at that distance from the camera. Note that there are two tables, one for crop-sensor cameras and one for full-frame cameras (want to know more – see our guide Full frame DSLR: do you really need one?).
For example, a Canon EOS 550D (1.6x crop-factor sensor) with zoom lens set to 24mm and an aperture of f/11 gives us a hyperfocal distance of 9ft, so focusing on an object nine feet away from the camera ensures that everything from half that distance, or 4.5 feet, will be in focus.
Below we’ve put together a cheat sheet for calculating hyperfocal distance on cameras with APS-C sensors, as well as full frame DSLRs. Feel free to drag and drop this infographic on to your desktop to save as a reference.
Final tips for how to use manual focus effectively
The only way to get consistently good results using manual focus is to
practise your technique! So here are a selection of manual focus challenges, after first calibrating your dioptre to ensure that the image you see through your viewfinder is as sharp as possible – this is particularly important if you wear glasses, which you remove when putting your eye up to the camera…
Set your camera on a tripod and autofocus on something large. Now rotate the little dioptric adjustment knob, just under the top right of the eyepiece. Rotate it back and forth until the place you focused on and the shutter speed/aperture display is really crisp and sharp. This sets your camera up for your eye.
Practise the camera-assisted manual focus technique (see Step by Step, p82). Select the centre focusing spot, shoot a few frames then select a different focus spot and try it with that. Compare your shots – do you see much difference in sharpness? The centre spot will always be the most sensitive.
Live View focusing is best done on a tripod. Place a stone or other object to focus on at the hyperfocal distance from the camera (using the hyperfocal chart on p83), then use the arrow keys to move the magnified area on the viewing screen to that spot. Zoom in to 10x magnification and focus.
Autofocus (using the centre spot) on a static subject and then switch to MF. Now recompose and shoot. As long as the camera-to-subject distance stays the same, your subject will remain in focus. This is a good technique in poor light where you can focus on a bright highlight and then ‘fix’ the setting.
PAGE 1: Overview; best scenes for manual focus; finding your manual focus controls
PAGE 2: Using manual focus in Live View; camera assisted manual focus; focusing for macro
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on Thursday, May 3rd, 2012 at 11:51 am under Photography Tutorials, Tutorials.
Tags: camera tips, DSLR tips, hot, landscape photography, macro photography, manual mode, photography cheat sheet