After I post question about D70 artifact when shooting to Sun I have got
quite a lot of reactions and huge load on server :-) Luckily I do not run
my own anymore :-)))
But back to the
problematic shot, which
is just 1:1 enlargement of
similar shot.
On both this effect appears:
This is what seems to me as reasonable and possibly correct answer:
"Think of the CCD elements as small buckets that fill with electrons
during exposure. When the buckets are full, they spill over and the
electrons run into adjacent buckets.
Another thing that happens is that, when one channel (RGB) blows out
(buckets fill), before the other channels, software interpolates what the
color at that location should have been. But that is based on a guestimate
at best. I think this is what caused the cross hatched effect in the border
of the blow out region"
But there is still interesting that just next pixels are almost dark. It
is kind of net. That what you see on enlarged version is 1:1 pixel
magnification from raw file. Effect appears only on top and bottom of
highlighted area from Sun, not on side.
There is also some possibility that it is cost by electronic shutter of
D70 (I have no idea how that kind of shutter works).
As you can read in text next to picture on my web it was shot with about
f4.5 and 1/1500 with 52mm focal length. Camera has 28-80G/3.5-5.6 Nikkor
zoom lens. But I believe glass has not participated on this. There were
suggestion that when lens is more closed f16- f22 it will not happened, but
than if I want to have narrow DOF this is not a option.
So what more? I do not know really. I am use to use difficult light
condition to get unusual shots and therefore this wasn't search for
breaking down digital future for me :-) just try out of shot I would
normally do. I wanted to see hoe D70 will handle it.
I really would like to know why this kind of thing happened and if it
is only on D70 or all digi cameras could have the same behavior.
Thank for your thought and if somebody knows more about CCD A/D and
possibly how CCD is filtered for RGB colors, maybe than you can tell me how
this can be avoided.
BTW: I was very happy with D70 handling and reactions. Absolutely perfect
no objection I like that camera very much. I just would like to know how to
avoid these kind of artifacts.
