Hi all,
<pixel-pitch> is commonly defined as the direct distance of the photosensitive detector elements on your imaging sensor. It is one of the factors that influences the performance of your imaging system but there are a lot more. I also was wondering about all the facts influncingt he process of imaging with digital sensors some time ago and digged a bit into it. Other important aspects are:
- numerical aperture
- aperture / f-stop
- ratio of wavelenth / diameter of aperture
- light diffraction / Airy disks
- Rayileigh criterion
- Modular transfer function (MTF), image contrast, object contrast
- signal to noise ratio of your sensor
- distortion characteristics of your lens
- etc, etc, etc,
here is one "rule of thumb" to get a number for distance of the objects to ge them resolved with an optical system
for common cameras, separation distance of
objects can be approximated:
f f 1
x = 1.22 * L * --- with --- = ---- = f-number
D D 2NA
x = distance between two objects
L = wavelength f = focal length
D = apertur diameter NA = numerical aperture
Some conclusion from all that stuff to consider:
diffraction sets fundamental resolution
limit independent of number of megapixels
depends only on the fnumber of lens, and
on the wavelength of light being imaged
it reduces smallscale contrast by
causing airy disks to partially overlap
tiny pixel sizes of high megapixel point
and shot cameras can only be exploitet
with high quality lenses and fnumber < 2
Or in other words: the sensor in your camera body is one thing to consider but there is another one in frontt of it - the lens with it' aperture, which is not of minor importance . Without a good lens the best sensor will only yield average image quality.
There is a saying amongst photographers: "Invest in glass!" :-)
Cheers and have fun
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