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Controlling depth of field

When a lens is focused on a subject, there is a certain range behind and in front of the subject that remains sharp, as mentioned in the part "the aperture". This range is called "Depth Of Field" or DOF. The photos show how depth of field varies with the aperture selected.

  1. Large apertures (e.g., f/1.7) yield a shallow field of sharp focus, rendering the background and foreground unsharp
  2. Small apertures (e.g., f/22) yield greater depth of field with more of the scene in focus

At a given aperture and focal length, depth of field also varies with subject distance: When the lens is focused on a close subject, depth of field is less; when focused on a distant subject, depth of field is greater. Focal length does also affect DOF; a wide angle lens will give a large DOF, while a tele lens gives a shallow DOF.

DOF preview lever

The preview lever can be used in all exposure modes to close down and lock the lens' aperture. This enables you to determine whether depth of field is sufficient. The lever is hinged and folds up against the handgrip when not in use. To use:

  1. Focus on the main subject.
  2. In A or M mode, set the desired aperture. In P or S mode, meter in the usual way.
  3. With film advanced, press the preview lever partly down and release it. Lens aperture will now be locked at the setting displayed in the data panel. "F" blinks in the data panel while the preview lever is used.
  4. Look through the viewfinder to determine DOF. When the lens is closed down, autofocusing does not operate and it is not possible to adjust the aperture setting. Also, the viewfinder image may appear dark, but this has no effect on exposure.
  5. To cancel the preview operation, press the preview lever all the way down and release it. The aperture setting can now be adjusted by using the up/down controls as usual. The DOF preview is also cancelled if the shutter is released with the lens stopped down.
  • When pressing the DOF preview lever down just a bit, the camera will stop down the aperture to the desired aperture. When pressing a bit more, the camera will stop down to the minimum aperture available on the lens (e.g., 22). The viewfinder gets very dark, but that's normal. Just press the lever all the way to the bottom and the viewfinder will be normal again.
  • The camera won't stop down the lens with the DOF preview lever if the film is not advanced.

Click to see descriptions of the different parts.

These pictures shows the impact of DOF. While they are composed and exposed the same, the picture to the left has a relatively large DOF while the one to the right has a shallow DOF. This is because of the chosen aperture. Note that the foreground subject is in focus in both cases.

Mounting index Bayonet mount Aperture stopdown pin Lens lock pin Lens release button Self timer LED Shutter speed up/down control DOF preview switch Lens contacts Aperture up/down control Focus mode switch Remote control terminal (covered) Matte screen Bottom contacts for accessories Battery compartment Rewind release Coupler for motorized film winding Coupler for motorized film rewind Handgrip PC socket Focus drive coupler Mirror Tripod socket Serial number Back release lock Lighting window Diopter adjustment dial Eyepiece shutter lever AEL button Accessory shoe Finder Film window Film advance lever On/off switch Multiple exposure button Strap eyelets Strap eyelets Strap eyelets Exposure mode selector Shutter release button Self timer switch Exposure adjustment button Frame counter Back release/ rewind crank / metering selector ISO adjustment button Film guide rails Film guide rails Back removal lever Take up spool Shutter curtains Film winding sprockets Accessory back contacts Back release latch Rewind prong DX contacts Back/top Front/bottom Film chamber Alphabetical