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Archived from groups: rec.photo.digital.slr-systems (More info?)
I don't know why I didn't notice this before but...
It seems that the distance scale on the Nikkor DX 18-70mm lens (the
lens that comes with the D70 as a kit) is set to be accurate only at
maximum telephoto. When set to widest wide-angle, the distance scale
is quite a way off. I did a test on maximum wide angle with a subject
(practically) at infinity. The distance when autofocussed was
(according to the scale) closer to the 2m mark than the infinity mark.
(I know the scale isn't linear, but was still suprised where the
autofocus seemed to end up.) The image came out fine. I also tried
manual-focussing and set the focus by setting the distance scale to
infinity. This second image was noticeably out of focus.
I'd already noticed that if a subject is in focus at a particular
focal length, changing the zoom doesn't move the focus ring and the
image goes out of focus. I assumed this is standard behaviour; but it
didn't occur to me until now that this implies that the distance scale
only works at a particular focal length.
Could someone set my mind at rest and confirm that the lens is
behaving as expected? The last time I used an SLR, I had separate wide
and telephoto lenses, and it's a bit embarrassing to confess to this
level of ignorance regarding zoom lenses.
Thanks.
I don't know why I didn't notice this before but...
It seems that the distance scale on the Nikkor DX 18-70mm lens (the
lens that comes with the D70 as a kit) is set to be accurate only at
maximum telephoto. When set to widest wide-angle, the distance scale
is quite a way off. I did a test on maximum wide angle with a subject
(practically) at infinity. The distance when autofocussed was
(according to the scale) closer to the 2m mark than the infinity mark.
(I know the scale isn't linear, but was still suprised where the
autofocus seemed to end up.) The image came out fine. I also tried
manual-focussing and set the focus by setting the distance scale to
infinity. This second image was noticeably out of focus.
I'd already noticed that if a subject is in focus at a particular
focal length, changing the zoom doesn't move the focus ring and the
image goes out of focus. I assumed this is standard behaviour; but it
didn't occur to me until now that this implies that the distance scale
only works at a particular focal length.
Could someone set my mind at rest and confirm that the lens is
behaving as expected? The last time I used an SLR, I had separate wide
and telephoto lenses, and it's a bit embarrassing to confess to this
level of ignorance regarding zoom lenses.
Thanks.