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08/04/2005 04:28:05 PM · #1 |
Hi
On my camera I have a depth of feild preview button. Not sure how this works. I hit it and it just gets darker. What does that mean.
Mabey the question is how do I get an image with out depth of feild where everything is in focus? |
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08/04/2005 04:30:45 PM · #2 |
| I have wondered this as well |
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08/04/2005 04:33:32 PM · #3 |
DOF preview gives the user an idea on how much will be in focus depending on the fstop selected.
Less dof = less in focus = lower fstop number (larger aperature)
More dof = more in focus = higher fstop number (smaller aperature)
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08/04/2005 04:34:38 PM · #4 |
When looking through the viewfinder the aperture is kept wide open so the scene is as bright as can be. When you press the DOF preview button the lens is stopped down to the aperture that you have set for the shot. This lets less light into the lens therefore making the scene through the viewfinder darker.
You should be able to make out the change in DOF when you use the preview.
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08/04/2005 04:34:54 PM · #5 |
| The depth of field preview button causes the aperture of the lens to stop down in order for you to see what your depth of field will be when you actually take the picture. It gets darker because when the aperture stops down, less light is coming through the lens. The smaller the aperture setting, the less light that comes through and the greater your depth of field. The greater the depth of field, the more that will be in focus. |
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08/04/2005 04:36:26 PM · #6 |
depth of field preview closes the lens opening to the aperture you have set. So if you set the aperture to lets say F16, pressing the button makes the lens opening 1/16 * focal length. If you own a lens which is F4, then the light now entering the lens and viewfinder is now only ~6% of what it was before which makes it dark.
For everything in focus, try using wide angle lens with high F# .. like F16 or F22. Also try focussing at hyperfocal distance..
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08/04/2005 04:37:04 PM · #7 |
The aperture is usually fully open while composing the shot, and then is placed at the desired size before the shutter is opened. The DOF preview closes the aperture down to the set size allowing you to see exactly the DOF the shot will have when taken. When the aperture is closed down, less light comes in and the view gets darker.
To shoot a scene with the maximum DOF (everything in focus) the camera must be focused at the hyperfocal distance. This is different for every sensor size and focal length, so search for a hyperfocal distance calculator and compute the exact distances for the conditions of the shoot. When focused at the hyperfocal distance, everything from half that distance to infinity will be in focus.
David
/edit: I am slow today -- ^^ none of that was there when I started typing. :(
Message edited by author 2005-08-04 16:38:34.
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