----- Original Message -----
From: "Tim Øsleby"
Subject: RE: My new Macro - a lemon.
As I say in a reply to WB:
I haven't noticed change of focal length when focusing. It is when
changing
aperture. Is that normal too?
My observation on the dust is simply based on what I see in my raw
converter. I have no idea of the magnification ratio. On screen the image
is
about 8 x 5 inches. The test shot was shot at about 20cm. It is visible
from
f5,6, really disturbing from f8, horrifying at f16. I assume that it fades
out when opening aperture proves that it isn't sensor dust.
I think you might consider showing us a picture of the glass, and dust blob
in question.
And perhaps a few web images of how the dust spec is afecting things.
Focal length should not change with aperture.
William Robb
