Thanks you Godfrey. I rely a lot more on you, than I do on the camera manual.
This means that I will get no help from the focus confirmation. And this means that I have a lot of practise in front of me, before I can get the hit rate I want/need. No short turns :-( Tim Mostly harmless (just plain Norwegian) Never underestimate the power of stupidity in large crowds (Very freely after Arthur C. Clarke, or some other clever guy) > -----Original Message----- > From: Godfrey DiGiorgi [mailto:[EMAIL PROTECTED] > Sent: 12. april 2006 04:08 > To: PDML > Subject: RE: How does the focus confirmation really work? > > > 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 >
