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The image seen in the G camera
viewfinders is always in focus irrespective of the fact that the camera may not
be focused to the correct distance. This is unlike the viewfinder image in an
SLR or classical rangefinder camera where all or some part of the image will
appear out of focus when the camera is not correctly focused. While the
difference in viewfinder image focus between the G cameras and other cameras
quickly becomes second nature to the user, it is the single most important
consideration in achieving the sharp focus of which the Carl Zeiss lenses are
capable. Several special focusing considerations are described below. Focusing at close distances and wide aperture settingsG camera owners are sometimes frustrated by out of focus photographs when
using the Carl Zeiss lenses at their physically largest apertures and shortest
focusing distances. When working under these conditions it is important to
remember that the position of the focus brackets in the viewfinder do not move
as the image is corrected for parallax. In addition, at the shortest possible
focusing distances, where the point which is the desired plane of focus is
placed within the focus brackets is also important. A third important consideration in achieving sharp focus under these
demanding conditions is to bring the focus brackets to the focus point by moving
the camera parallel to the scene rather than by pivoting the camera. At short working distances, placing the object you wish to be the plane of
focus at one or the other of the brackets maximizes the distance between the
camera’s autofocus windows. Maximizing the distance between the autofocus
windows improves the precision of focus. Place the object to be focused upon at
the left focus bracket for distances of 0.5 m. to less than 1 m. Place the
object to be focused upon at the right focus bracket for distances of 1 m. to 2
m. At greater distances, placement at one or the other of the brackets becomes
less important and the object can be placed between the brackets. At their shortest possible focus distances and largest physical apertures all
lenses have extremely limited Depth of Field. Generally speaking, under these
conditions the total DOF is on the order of 19-mm. or 0.75-in. Six millimeters
of that total DOF lies before the plane of focus and remainder of the DOF lies
behind the plane of focus. With such extremely limited DOF, it is impossible to
render in overall sharp focus any object which itself has depth. The best results under these conditions are achieved by bringing the focus
brackets to the focus target by moving the camera in parallel with the scene.
Pivoting the camera to bring the focus brackets to the focus target, locking
focus, and returning the camera to the scene will render the scene out of focus
as the focus distance locked in memory will be inaccurate. Assume that you want to photograph a scene at 1.5 m. using the 90-mm.-lens
set at f/2.8. Compose the scene as you wish it to be in the viewfinder, meter
the scene as you wish it to appear, and lock the exposure using the AEL lever.
Moving the camera parallel to the scene, bring the focus brackets to that point
in the scene you wish to be the plane of focus. Place the point of focus at the
right focus bracket and partially depress the shutter button to lock focus.
Again moving the camera parallel to the scene, recompose the scene as you wish
it to be and release the shutter. Zone Focus
The focus distance for the G cameras can be preset for candid photography.
Switch the camera to Manual focus mode. Using the manual focus dial, set the
focus distance to the desired distance using the distance shown in the LCD
window on the top of the camera. Once set, the camera will drive the lens to the
focus distance set in the LCD window when the shutter button is depressed or the
Focus Lock button on the back of the G2 camera is depressed. Infinity Focus
The focus distance for the G cameras can be set to infinity using the
camera’s Manual Focus mode. Switch the camera to Manual focus mode. Using the
manual focus dial set the focus distance to infinity using the LCD window on the
top of the camera. Once set, the camera will drive the lens to infinity when the
shutter button is depressed or the Focus Lock button on the back of the G2
camera is depressed. Hyperfocal Distance, estimated distance, or measured distance focusing
The G cameras can be set to a Hyperfocal Distance, estimated distance or
measured distance using the camera’s Manual Focus mode. Switch the camera to
Manual focus mode. Using the manual focus dial set the focus distance to the
desired distance using the LCD window on the top of the camera. Once set, the
camera will drive the lens to the desired distance when the shutter button is
depressed or the Focus Lock button on the back of the G2 camera is depressed. When the desired preset distance is greater than 15 m., 49 ft., set the
camera to infinity and close down the aperture until the subject material you
wish to be more or less in sharp focus falls within the DOF for that aperture.
Read more about the advantages of this focusing technique in an article by
Harold Merklinger at: http://fox.nstn.ca/~hmmerk/DOFR.html. Focusing when the autofocus does not want to focus
The conditions under which the autofocus of the G cameras cannot determine
focus are described in the G cameras owners’ manuals. The techniques to aid in
autofocus described in the owners’ manuals are effective. In addition to those
techniques, G camera owners have found that the following techniques are also
effective. When the camera signals that it cannot focus, rotate the camera about its
lens axis while holding the shutter button partially depressed. Many times, this
will allow the camera to find the point that you wish to be the plane of focus.
Once the camera has locked focus, rotate the camera back to the desired
viewfinder composition without releasing the partially depressed shutter button
and shoot the frame. Another technique to aid in focusing is to move the point of interest to
either the left or the right focus bracket. Many times, this will allow the
camera to focus. |
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Focusing The G Camera
