How do you use DOF Preview and when do you use it?

[Larvin72]

Newbie wants to ask how to use the DOF feature and when do we use it?

[Blencogo]

Hi Larvin72,

Modern DSLR cameras keep the lens aperture wide open when you are composing and focusing.  This gives the brightest image possible in the viewfinder and the smallest depth of field to find an exact focusing point.  The lens then stops down to the chosen f-stop when the shutter is released and the depth of field increases the more you stop down the lens.

At f3.5 only objects at the same distance from the camera as the focusing point will be sharply in focus but at f22 you may find that everything between 5 meters and 1,000 meters is sharp.

All the DOF Preview does is to stop down the lens to the value which will be used for the photo so you can see in the viewfinder what will and will not be in focus.

Unfortunately the image gets dimmer the more you stop down the lens.

Hope this gives you some ideas on using DOF (Depth of Field) to good effect in your pictures.

What camera do you have?

[Larvin72]

Hi Blencogo,

Thank you for that very deep explanation. I have the a580, but i still dont know how to use the DOF button.