Re: paleonet Digital Images and Depth of Field

[Tom Whiteley <tomw@xxxxxxxxxxxxxxxx>]

Actually depth of field is certainly a function of f-stop but it is 
not truly a function of focal length. Short focal length lens have 
greater depth of field when compared to longer focal length lens on 
subject matter photographed from the same position, i.e. the image is 
smaller. If one changes the camera position to get the same image 
size on the film plane at the same f-stop the depth of field is the 
same. Also if one enlarges an image taken with a short focal length 
lens to the same image size the depth of field is the same. There is 
no free lunch.

Also the sharpness of a lens falls off noticeably at f-stops smaller 
than f 11. This is not very important with most digital cameras 
because the limitation is the resolving power of the CCD.
Tom Whiteley
tomw@rochester.rr.com