If you find that certain lenses do not produce the desired results with autofocus, you can fine-tune autofocus for each lens using the AF fine‐tune option in the setup menu. AF tuning can also be used to offset focus from its normal position for a deliberate defocus effect. Note that AF tuning is not normally required and may interfere with normal focus; use only when necessary. Check focus before making any adjustments using Saved value or Default option.
Note that fine-tuning applies only with phase-detection AF (viewfinder AF) and is not available during live view.
Before beginning AF fine-tuning, ready the materials you’ll need and familiarize yourself with the AF fine-tune menu.
The AF fine-tune menu
The AF fine-tune menu contains the options listed below.
|AF fine tune (On/Off)||
|Saved value||Tune AF for the current lens (CPU lenses only).|
|Default||Choose the AF tuning value used if no previously saved value exists for the current lens (CPU lenses only).|
|List saved values||List previously saved AF tuning values. If you are using more than one lens of the same type, you can add an identifier to the lens name (for example, the last two digits of the lens serial number).|
What You'll Need
Ready the following:
Ready a D4S camera and a CPU lens.
The ideal target is flat and features sharply contrasting areas of solid black and solid white. The target in this example is a white stripe on a black background; the stripe should be about 1.5 cm wide.
Prepare the subject and ready the camera as described baelow.
Fine-tune autofocus not in a poorly-lit interior but outdoors or in other brightly-lit locations. If it is adequately lit, we recommend choosing a location you would ordinarily use for photographs.
Position the target at about the distance where a human subject would fill the frame in portrait ("tall") orientation. Place the target at right angles to the optical axis, parallel to the camera body.
Choose single-point AF and select either the focus point you use most often or the center focus point, then frame the target and take a picture using autofocus.
Follow the steps below to fine-tune autofocus. Note that fine-tuning applies only with phase-detection AF (viewfinder AF) and is not available during live view. You may have difficulty focusing at infinity or at the minimum focus distance while fine-tuning is in effect.
1 Select AF fine-tune.
Highlight AF fine‐tune in the setup menu and press .
2 Select AF fine-tune (On/Off).
The AF fine‐tune (On/Off) option in the AF fine-tune menu is used to turn AF fine-tuning on or off. Highlight AF fine-tune (On/Off) and press .
3 Select On.
Highlight AF Fine-tune(On/Off) and press to enable AF fine-tuning for all saved lenses and return to the AF fine-tune menu (to disable AF fine-tuning, select Off).
4 Select Saved value.
To fine-tune focus for the current lens, highlight Saved value and press .
5 Select a value.
Select positive values to shift the focal point for autofocus away from the camera, negative values to shift it towards the camera.
The camera can store values for up to 20 lenses; to fine-tune additional lenses, attach them and repeat the steps above. Note that fine-tuning values are stored by lens name (focal length and maximum aperture) and that only one value can be stored per name, although values recorded with teleconverters attached are saved separately. To delete previously-saved values, select List saved values, highlight the desired lens, and press .
Photograph the target as described in “Setup” and check focus (if the effect is hard to see in the camera monitor, transfer the picture to a computer, where it can be viewed at higher resolution). Adjust fine-tuning in the desired direction and repeat the process until you are satisfied with the results. Before each shot, change the focus distance by a large amount prior to engaging autofocus.
The options in the AF fine-tune menu can also be used for the tasks below.
Storing Values for Additional Lenses
Fine-tuning values for additional CPU lenses can be added using the Default option as described under "Fine-Tuning".
Managing Previously-Saved Values
To view previously-saved values, select List saved values in the AF fine-tune menu.
Lenses are listed by focus distance and maximum aperture, and can also be assigned an identifier as described below. To delete a lens from the list, highlight it and press .
To distinguish them from other lenses with similar names (or, if you own multiple lenses of the same type, to identify the particular lens used for fine-tuning), lenses can be assigned unique two-digit identifiers.
Highlight a lens in the saved values list and press to display the lens identifier. Press or to choose an identifier and press to save changes and exit.