I was thinking the same thing. At f11, depth of field helps a lot. I love my *istD, but in low-light, autofocus is definitely not accurate. I can't imagine even attempting it with a 10 stop ND. I think I would focus manually and then screw the filter on. Paul
> Hmmm .... getting "correctly focused images pretty much all the time" > doesn't sound so good. Getting correctly focused images all the time > sounds a lot better. Can't help but wonder how much of a role DOF plays in > your correctly focused images. I'd be interested to know how well the > focus looks at wider apertures, like 2.0. That would seem to be a better > indication of how well the camera is focusing. Just ca;ll me an old > fashioned skeptic ;-)) > > Shel > > > > [Original Message] > > From: Herb Chong <[EMAIL PROTECTED]> > > > i read about this "slow or useless AF performance in low light" on the > *istD > > comment and i wonder every time what is really going on. i shoot a lot of > > waterfall shots with a 10 stop ND filter mounted. that gives me typically > 8 > > second exposures at f11 or f13 at ISO 200. i set the camera to point > select > > AF mode, choose a focus point, press the shutter release half way, it > > focuses and lock correctly (usually on the first try), and i take my > > picture. the 10 stop filter is mounted while i am doing this. it's almost > > impossible to see *anything* in the viewfinder except the readouts, yet > the > > AF works and i get correctly focused images pretty much all the time. > > > >
