FDanB@aol.com wrote:
>Am I remembering something incorrectly or does image size on the
>film/chip plane change with aperture? I could swear it does but I don't
>know from where I pulled that info. Or, perhaps I'm just losing my mind.
>
>I'm helping a friend edit a chapter in his book and sure don't want to
>suggest something wacky.
>
>Thanks in advance for input.
>
>Dan
>
>www.danburkholder.com
>
>www.TinyTutorials.com
>
>
>
>
>
You have lost your mind. In a properly designed lens (like you will
use), reduction of aperture will reduce the amount of optical signal
level to the array or film, increase the depth of field and if the lens
were perfect would increase the blur circle..meaning the spatial
resolution would get worse. The image size should not change. IF the
stop (aperture) was put in the wrong place, it will cause vignetting
since you are cutting off part of the image. Sometimes a compromise
design like a convertible lens will show focus shift when you use one
element AND if you looked closely enough, would show vignetting. If the
image size changed you would not be able to focus wide open and stop
down for your photo without some image size change.
Now, having said that, someone will come up with an optical system that
can show size change with aperture, but it won't be a lens you will use....
Received on Wed Mar 9 19:04:14 2005
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