On Mon, Oct 23, 2006 at 07:16:00PM -0400, Doug Franklin wrote: > John Francis wrote: > > > It's odd how people keep repeating this, and yet there are > > several of us on this list who find the AF quite fast enough > > to shoot race cars travelling at anything up to 200MPH. > > True, but just like doing it with manual focus, the key is to manage the > angular velocity of the "fast thing" through the field of view. :-)
I've found the AF can actually keep up with cars approaching head-on at three figure speeds. > That said, I'm perfectly happy with Pentax AF for motorsports except for > one little thing that I can correct for. > > As I've discussed here before, including recently, it seems like when > I'm panning, the AF is a couple of feet behind my eyes or the "lock > time" hoses me or something. To get the cockpit at frame center to be > the in focus part of the image, I have to set the AF point to the one on > either side of center (depending on the direction of travel) and keep > the camera's center AF point centered on the cockpit area of the car. I'd agree with this observation. In general I tend to use the sensors on the row below center, rather than the middle row. In fact a year or two ago I was shooting with the 1.7x AF adapter on my 300/f2.8, which restricts me to just the central AF point, and that combination didn't work all that well with the head-on shots of cars cresting a hill. The next day I went back with the FA 250-600 and got a much higher hit rate shooting from exactly the same point. > > Of course, this could also be more of an affect of the center of the > car's turn not being the same point as my center of rotation as I pan > the camera. > > Or it could be a bit of both ... or neither ... or something totally > different. :-) > > > That doesn't mean there isn't room for improvement; I'm > > really looking forward to the K10D with DA* SDM lenses. > > But I miss a whole heck of a lot more shots by tripping > > the shutter at the wrong time, or not quite getting all > > the car in the frame, than I do to auto-focus failures. > > You and me both, not to mention panning at the wrong rate. I'm hoping > that SR will help increase my "keep rate" by helping to eliminate any > vertical shake I'm introducing as I pan. I'm not sure that the Pentax SR system will work at all when panning; it only appears to have on/off settings, not a vertical-only mode. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
