Re: Gabriel Jacob's blurry pics-

[P3D Norm Goldblatt <normgold@xxxxxxxxxx>]

Of course, if the lens is poor quality or maybe some of the elment
spacings are not right due to loose spacers, you might have problems at
larger apertures. All lens 'abberations' depend on the aperture- some
even go as the aperture squared. Depth of focus also decreases with
decreasing (f#)^2, so focus is more critical at low f#s.   Don't know
enough about your camera, but there could be a disagreement between
viewfinder and focal plane, if it's SLR or TLR.  I would also take a
picture of something with varying distances, like the lines in a road,
taken close to the road surface (don't forget to look up every once and
a while!).  Set the lens for various distances and f stops and you
should be able to tell what's happenin'.
You know, if the lenses are not perpendicular to the film plane you
would have problems, more acute as the f# decreases. Camera have any
dents?! Both right and left 'channels' out of focus by same amount? This
would happen before any single channel was out of focus because of this
problem, though. 

Report back in- be fun to try to figure it out, without ever seeing the
camera or the pictures! (Something like Richard Feynman's "Surely you're
joking---) One chapter is called "I fixed a radio by thinking"- a
charming story about deducing what's wrong with something without
tearing it apart and then going right to the broken part to the
amazement of a friend of his father.
Norm
http://www.aimnet.com/~normgold

Norm


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