I am trying my hands around using Depth of field preview button with my Nikon D90 and its 18-105mm Kit lens. I read some online material as well have seen some videos about using it, but so far I'm not having any luck.

I've tried the following:

  1. First i set my aperture to 5.6,focused on some object 5-6 feet away adjusted the light meter and than pressed the DOF button.
  2. Again changed the aperture to 11 with same steps than to 22 with same steps.

I don't see any changes when I do that, though. Now this means either I am really dumb (:)) or i am missing something. Can any one help me figure this out?


2 Answers 2


I hate to say this, but first make sure you're pressing the right button, as I always press the wrong one. There are two similar buttons. One is the function button near the top of the lens, and the DOF preview button is almost under the lens.

If you press the DOF button, even with the aperture wide open, it will make a very clunky sound, like when you press the shutter and the mirror bounces up.

At f/22 the image through the viewfinder should get much darker.

I'm pretty certain you can't reprogram that button on the D90.

Edit: picture worth 1000 words! This is a D80, but button is in the same position (from digitalreview.ca)

DOF preview button

  • \$\begingroup\$ OK There are 2 buttons one has name fn and i believe that is function button and i am pressing the other one on the opposite side of the 'fn' button ,but have not noticed any sound. will check again \$\endgroup\$ Dec 12, 2011 at 9:04
  • \$\begingroup\$ If you hold the camera normally, with your right index finger on the shutter, this DOF button is tucked underneath the lens, where your pinky finger. Almost underneath the lens. Hang on, will post an image. \$\endgroup\$
    – MikeW
    Dec 12, 2011 at 9:22
  • \$\begingroup\$ :((((( i am 1000% sure i am pressing wrong button. i saw the camera manual but pic was not much clear will check once i am back @home +1 for the pic , a picture is more than thousand words \$\endgroup\$ Dec 12, 2011 at 9:36
  • \$\begingroup\$ Where does the "very clunky sound" come from? My Canon kit lens only makes a faint "ssst" when it closes the aperture. \$\endgroup\$
    – AndreKR
    Dec 12, 2011 at 9:56
  • \$\begingroup\$ Not sure. It sounds like the mirror moving up, but it must be the mechanism that sets the aperture. Really loud on the D90, sounds like the shutter being released \$\endgroup\$
    – MikeW
    Dec 12, 2011 at 10:09

Unless you have programmed the DOF button to do something else, which you can on most DSLRs, you should see a difference as long as there are objects at different distances in your viewfinder.

At the very least, the view has to get darker when stopping down. If it does not, then you DOF button is doing something.

If it is, you will see a change in blurriness with objects that are in front and in back of your focus distance. The change is always more pronounced towards you. So, lets say you focused at 6' away, an object at 4' away will be more blurry at F/5.6 than F/22. An objet at 8' away will also be more blurry at F/5.6 than F/22 but the difference will be less so.


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