Manual Focusing with Nikon CP5700

Sometimes it’s difficult to see in the viewfinder where to set the dial for sharpest focus. (Focus Confirmation, a shooting menu selection, can make this easier.) Still, if you are shooting in Auto Focus and find that the camera is hunting for focus, at least Manual Focus will hold still once you’ve set it. Both AF and you may have difficulty recognizing sharp focus if the scene is dim and/or does not include some contrasting edges.

Note: The Nikon 5700 User’s Guide shows the closest normal focus as 50 cm. The author’s camera allows Auto Focus at 31 cm, and the Manual Focus scale turns from red to white at 31 cm.

Close-up Conditions

In MF mode, the camera can be focused from 3 cm (a little over one inch) to infinity, only if the Zoom control is set to between 9.2 mm and 11.8 mm.

To do that, move Zoom toward telephoto (T) until the MF scale changes color from red to white.

Note: An exposure can be made even when the scale is red, but the picture may not be in focus.

When the scale changes from red to white, the actual Zoom setting will be at about its minimum value (9.2mm).

At the other end of the Zoom range, the MF scale will also show red until the Zoom is moved from its maximum of 71.2 mm back to 11.8 mm. Therefore, Manual Focusing in close-up operates only within the Zoom range of 9.2mm to 11.8mm (36mm to 46mm equiv.). In the Zoom scale, this is within the setting shown by two blocks: 

Unfortunately, you cannot tell the exact numerical setting of either the Manual Focus or the Zoom control until an exposure is made and the data for that exposure is examined. You have to rely on the color of the MF scale. When the scale is white, you can adjust the focus from 3 cm to infinity without changing the Zoom control. Also unfortunately, the Zoom control is motor-driven, and so it cannot be set precisely, other than by trial and error. Usually for me, that means backing and forthing once or twice. Jogging the zoom is easier if you set your zoom speed on the setup menu to low.

Note: The Manual Focus setting is retained as set even if the camera is turned off. To switch back to Auto Focus, simply press and release the MF button.

Remember that if you turn the camera off, the Zoom setting reverts to Wide, even though the MF setting stays where you left it. On the other hand, if you switch from User Set 1 (or 2 or 3) to User Set A and back without changing the Zoom setting, it too will remain where you left it (provided you do not turn the camera off ).

The Auto Off function, which shuts down the camera after a set interval, does not affect the Zoom setting.

Manual Focus is set in 64 steps (see chart above). At the close-focus end of the range, each step changes the focal distance by 1 cm, up to about 20 cm (approx. 8 inches). Beyond that point, each click of the Command Dial represents greater and greater increments. Because the depth of field also increases as the lens is focused farther and farther away, this is not a problem in accurate focusing.

So, what's it all mean for taking pictures?

  The short answer is, it takes practice to learn to use the camera the way you used to with your old 35mm SLR. There's no point in complaining that you'd rather twist a ring on the lens barrel, or that you want continuous focusing rather than preset steps. It would be nice, of course, to have the zoom automatically set to where it needs to be for manual focus, just as the f-stop limits are there without your having to remember them. This is the way the camera is made, and it's a good piece of machinery. Its peculiarities can be learned, the same way photographers learned to pull the dark slide on their sheet-film cameras (how many blank--or black—films were discovered in the darkroom in those days?)

At first, I had some difficulty with holding the camera and pressing that small button to focus manually. But I found that the traditional way, supporting the camera with my left hand, elbow close to my body, put the button in exactly the right place. And yes, it could be just a little larger for my hands. To locate the other three buttons, I have to bring the camera down and look. But the focusing button is easy to find by feel.

What's harder is to see when the camera is in focus, particularly in dim light. That's at least partly due to my aging eyes. And the much-extended depth of field of the CP5700 makes visual determination of sharp focus harder yet. Wide open, the depth of field is like a 35mm camera with normal lens set at f8.

I loved the TTL focusing of motion picture cameras and camcorders, with which you zoomed in all the way, focused on a much-enlarged image, then zoomed back out to frame the shot. The focus held for any zoom setting, unlike most SLR lenses I've used. Well, guess what? Manual focus with the CP5700 is just like your camcorder! Here’s a set of shots from a tripod, focused on a target 2.1m from the lens, at three different zoom settings, then all reproduced at the same size. The image on the right is enlarged about six times the image on the left, a little over twice the enlargement of the middle image.

Zoom: 71.2mm; Dist. 2.1m.                     Zoom: 21mm; Dist. 2.1m.                         Zoom: 8.9mm; Dist 2.1m.

  Apparently, the lens is sharper at 21mm than it is at either 71.2mm or 8.9mm. Notice, however, that the right-hand photo was exposed at f2.8, while the left-hand image was at f4.7 and the center image at f3.5. (The camera was in Auto Exposure mode for all shots.)

For a comparison, here is the same zoom as the right-hand image above, except with aperture of f4.5. Next to it, at f2.8, is the same zoom, same distance, but with Auto Focus:

It appears that more of the difference in sharpness is due to the focal length (zoom) setting than to aperture. This may explain why Nikon limits us to a focal length near the middle of the zoom range for close-ups. It also suggests that for maximum sharpness, it’s better to use that middle-zoom range and move the camera closer to or farther from the subject to get the desired image size.

Conclusions

1. To use Manual Focusing with the greatest efficacy, if your distance is greater than the close-up range, zoom in all the way and set the MF dial, then zoom back to frame.
2. Use the chart in this document to estimate how many clicks it will take to change your focus to where you want it.
3. Remember to turn off Manual Focus when you want to shoot Auto. And remember that the Manual Focus will revert to the last setting you used in that User Set, even if you’ve turned the camera off and removed the battery.

  Don Skiff
January 13, 2004

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