Controlling Depth of Field
In almost most panoramic pictures you will want everything to be in sharp focus so you want to make sure you are maximising your depth of field. The easy way to achieve this is to stop the lens down to its smallest possible aperture f/22 perhaps? and focus on infinity. Doing this does not always give you maximum depth of field and your lens will give its worst optical performance at the minimum aperture because of the diffraction. To get best results you need to stop and think about the depth of field you really need for the scene, and also take into account the optical characteristics of your camera and lens.
If you shoot a panorama indoors the furthest thing from the camera is quite possibly to be only a few metres away, so there's no need to have a huge depth of field. If you stop down to f/22 you will not only end up shooting very long exposures and risking camera shake, but possibly get a disappointingly soft image because of diffraction. You need to totally understand the hyper focal distance and diffraction.The hyper focal distance is the distance from the camera to the optimum focusing point to achieve maximum possible depth of field.
The distance varies accordingly to the lens focal length (f), lens aperture used (a) and the circle of confusion of the lens (c, which is a constant: 0.036 for 135 format):If your lens has markings on it (usually the case for SLR lenses) you can use these to control depth of field (see below). You can also work out the hyper focal distance mathematically using the equation above. My Nikon Cool Pix 990 digital camera allows me to manually set the focus, by setting the distance from the camera that I want to focus on - by knowing the hyper focal distance,
I can correctly set this to maximise depth of field. (Note however that in practice the automatic 'landscape' mode will cause the camera to use the hyper focal distance and achieve maximum depth of field).If you want to work out the hyper focal distance for your lenses you can use the equation above, note for digital cameras you will need to know the 135 format "equivalent" focal length. It can also tell you the near and far limits of depth of field for every aperture of your lens, and work out the aperture and focus point you should use to achieve a specific near and far distance.
Controlling depth of field In most panoramic pictures you will want everything to be in sharp focus so you want to make sure you are maximising your depth of field. The lazy way to achieve this is to stop the lens down to its smallest aperture (f/22 perhaps?) and focus on infinity. Doing this does not give you maximum depth of field and your lens will give its worst optical performance at the minimum aperture because of diffraction. To get the best results you need to stop and think about the depth of field you really need for the scene,
and also take into account the optical characteristics of your camera and lens. If you shoot a panorama indoors the furthest thing from the camera is quite likely to be only a few metres away, so there's no need to have a huge depth of field. If you stop down to f/22 you will not only end up shooting extremely long exposures and risking severe camera shake, but probably get a disappointingly soft image because of diffraction. You need to understand the hyper focal distance and diffraction. What is the hyper focal distance?The hyper focal distance is the distance from the camera to the optimum
focusing point to achieve maximum depth of field. The distance will vary according to the cameras lens focal length (f), lens aperture used (a) and the circle of confusion of the lens (c, which is a constant: 0.036 for 135 format)!
