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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.

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Oh and also – mattdm Dec 31 '11 at 15:04
You said: but when I change from f/4 to f/10, it doesn't change much. The smaller F number indicates wider aperture. Wider aperture means more shallow depth of field. So, raising from F4 to F10 will make the situation worse. Zoom in as much as you can, get far away from your subject as much as you can, decrease the aperture as much as you can. Also, when you zoom in fully you won't be able to lower the aperture after a certain point, that is a limitation in the lens of your camera. So, to get the "real" effect of shallow depth of field install GIMP/Photoshop on your computer. :) – TheIndependentAquarius Dec 31 '11 at 15:44
Thank you all. The answers and links provided were very helpful to understand my question. – AntonioJunior Dec 31 '11 at 18:11
up vote 20 down vote accepted

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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Ooh. Good catch! – mattdm Dec 31 '11 at 19:51
Wow, didn't see that coming. – dpollitt Dec 31 '11 at 21:07
Nice answer. :) – TheIndependentAquarius 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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protected by John Cavan Apr 16 at 0:04

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