Badly focused shot as the subjects are not focused and the background is. Autofocus can produce these kinds of results.
Focused on the monitor. quite narrow depth of field.
Everything is in focus. the more you close the iris the easier you can achieve deep focus.
Focus shifts from the screen to the viewer. here the deapth of field is very narrow. to achieve this you should zoom in a bit and open aperture as much as possible.
Auto focus can result in unstable focus.
The Shoot – Setting up the equipment
Focus
Try to avoid automatic focus. You will get into trouble for example if somebody walks in front of the image or the focus starts to ‘breathe’, meaning the camera is searching for focus back and forth. This easily happens in dim lit situations like when filming video installations. In dim light the aperture needs to be wide open to allow enough light into the camera. A wide aperture means that the depth of field (=the area which is in focus) is narrower making focus even more critical in such low light conditions. There are situations where manual focus pulling is not possible and when auto focus might be an option. The auto focus function varies significantly in different cameras and some are much better than others, so experiment first before making your final footage.
If you are in controlled circumstances and you have the time, zoom in on the object, take focus and re-frame the image. If you have to take focus in the middle of the shot avoid disrupting the shot by heavy movements on the focus ring but employ a slow tweaking focus instead. Some cameras have the possibility to stay on manual focus and push a button to get the camera to focus automatically for an instant. The camera focuses as long as the button stays down and goes back to manual mode when released. This can, in many situations be useful. If in doubt, keep the frame as wide as possible as it is then not so obvious that the image is slightly out of focus.
Keep in mind most of the cheaper HD cameras have rather poor focusing tools. The displays do not have enough resolution to show the focus properly and as the definition is so much higher focus becomes more critical. Using an external monitoring is almost always necessary.
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