I am sorry if my question is too naive, but I am a complete beginner in photography, and I think I still need to understand well what aperture is. I have a Fujifilm S4000 camera, and I know I can't do with it everything that a professional camera does.

I wanted the background of some pictures to be blurred by changing the aperture, but I don't get the results I expected. I think it also has to do with the focal length, am I right? Here are the settings to the two photographs I compared:

Picture 1
Aperture: ƒ/4
Exposure: 1/2 s
Focal length: 7 mm

Picture 2
Aperture: ƒ/10
Exposure: 2.6 s
Focal length: 7 mm

I would like to know what settings I can use to get the background to be blurred. I know that with smaller aperture values, the area around the object in focus will be more blurred, but when I change from ƒ/4 to ƒ/10, it doesn't change much.


There is NO difference at ALL because the physical aperture has not changed.

The Fuji Finepix S4000 simulates a small aperture using an ND filter. When you stop-down the ND filter slides into the optical path. The Aperture written in the EXIF data is adjusted to reflect the transmittance of the ND filter, but note that since the size of the opening has not changed Depth-Of-Field does not change either.

Not only do such cameras have very small sensors and extensive depth-of-field but they are also extremely prone to diffraction. If the aperture were actually stopped down to F/10, images would get quite blurry.

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  • 5
    Ooh. Good catch! – mattdm Dec 31 '11 at 19:51
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    Wow, didn't see that coming. – dpollitt Dec 31 '11 at 21:07
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    Nice answer. :) – Aquarius_Girl Jan 1 '12 at 1:26

At a focal length of 7mm, you will be hard pressed to see much difference in depth of field. DOF will be enormous regardless of aperture.

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