From: Tim Øsleby <[EMAIL PROTECTED]>
I wasn't accurate when saying this. I was thinking about the red
blinking
light telling me what focus sensor that is in use. You can switch
those off.
The green polygon is impossible to turn off, I believe.
Don't let it bug you.
How do you turn off the focus confirmation in the istDS? That green
polygon seems to be impossible to get rid of.
I know many turns the focus confirmation off.
I always turn off the focus spot overlays when using a manual focus
lens. You can't turn off the green indicator. With manual lenses,
only the center AF sensor is active anyway, there's no need for an
indicator spot on the focusing screen.
In my opinion, the focus confirmation on manual focus is accurate
enough to focus a lens in the 14-135mm focal length range that is set
apertures smaller than f/3.5. F/2.8 is pushing it. This is in
contrast to letting the AF work with an AF lens, where it will
succeed in nailing the focus right on the money even with an
FA50/1.4. I conjecture that the difference in accuracy is due to the
fact that only one sensor is operating ... when you have all 11
sensors operating, they could be adding more information into the
contrast comparison and thereby improving the accuracy.
With a very long lens, and particularly one with a maximum aperture
in the f/5.6 range or smaller, it's probably not accurate enough to
rely upon. Make sure the focusing screen is properly focused to your
eye with the diopter control, and then learn to get the best focus
point by watching the out-in-out of focus transition and practicing.
The center AF sensor on my DS covers a slightly oblong rectangular
region the starts about 1-2mm above the focusing screen center and
ends about 3mm below it, and is 2mm wide. It's offset about 1mm to
the left.
While I'm at it: What area does the spot meter cower? Online
resources or
explanations on this too, please.
The spot meter pattern is constrained to be approximately the center
circle of scribed on the focusing screen with the standard or
"divided matte" screens. See page 131 in the *ist DS instruction
manual for an illustration at the bottom of the page. In my
sensitivity measurements, it proved just a little larger than the
illustration suggests.
Godfrey
