Pixel Size

[aa00601]

hi

i have a promblem with my diploma exercise. i need to know the size of the pixel at the sensor or the focal legth of Nokia 5140 and Sony Ericsson K700i. Does anyone knows what "4mm" and "1:2.8" means (it's written near the camera)?

[seedub]

Those things only pertain to the camera, they have nothing to do with the screen and the pixels. 4mm is the size of the camera lense and the 1:2.8 is a ratio and I am not sure what its actually for. You should also delete your other thread, you dont need to start a new thread with the same question just because you havent gotten an answer yet.

[aa00601]

Thanks.

what do you mean by camera lence? is it the focal length?

[seedub]

I mean the diameter of the actual lense.

[Memzee]

*thread moved to Digital cameras section*

[sidneylopsides]

The 4mm is the focal length, the distance from the lens to the sensor, the 1:2.8 is the aperture F number, the ratio of the diameter of the aperture to the focal length. The lower the F number the larger the aperture.

[Seanjuan]

Ah...so lower F # means higher megapixel, or is megapixel just resolution alone?
I think I'm confused. Sorry.

[aa00601]

sidneylopsides,
are you sure for the focal length is 4mm? Please it's very importand. it' for my diploma exercise.

[sidneylopsides]

Ah...so lower F # means higher megapixel, or is megapixel just resolution alone?
I think I'm confused. Sorry.

The F number has no relation to the number of pixels. It refers purely to the lens.

sidneylopsides,
are you sure for the focal length is 4mm? Please it's very importand. it' for my diploma exercise.

4mm is the focal length.

Have some links :)
Focal Length (http://www.dpreview.com/learn/?/Glossary/Optical/Focal_Length_01.htm)
Aperture (F number) (http://www.dpreview.com/learn/?/Glossary/Exposure/Aperture_01.htm)
Pixels (http://www.dpreview.com/learn/?/Glossary/Camera_System/Effective_Pixels_01.htm)

[Manticorp]

so a lower aperture means that u get more detail (or less 'real area') in a shot? and a larger aperture means u can fit more in? so u can get more into a megapixel? ahh I dunno xD

[sidneylopsides]

so a lower aperture means that u get more detail (or less 'real area') in a shot? and a larger aperture means u can fit more in? so u can get more into a megapixel? ahh I dunno xD

Nope.
Aperture only affects the amount of light and depth of field, you still get the same image size and detail.

[Manticorp]

ohh right I gotcha, sorry I can be so stupid at times XD I gotcha haha...thank you =P