Archived posting to the Leica Users Group, 1996/04/23
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 01:08 PM 4/23/96 -0400, you wrote: >> Another thing is the ability of the camera to stop the lens at the right >> spot when it's focusing. I could know exactly where to put the focus, but >> being able to execute it quickly might be compromised as opposed to a human >> who racks the focus back and fort and observes how focus goes in and out, >> which is why AF is best for fast moving subjects. > > I am sure that contrast does play a role too, and I have my >doubts about PP's test methodology. You lost me on the previous >paragraph, though. What did you mean? Sorry Gary, I dropped a "T." <g> I meant "IT could know..." the camera could know where it's supposed to stop the lens, but the forces of moving the elements makes it over- or under-shoot the perfect place for it to come to rest. When we focus manually, we don't just turn the ring to the perfect spot, we rack the lens back and forth and watch it pop in and out of focus. At least, when we have the time. And in the process, we find the ideal spot for focus. How far off does an AF system have to miss perfect focus to reduce image quality? I'm sure it's not much. In this case, I think Pop Photograpy is able to test pretty adequately, and it seems most people's experiences agree with the results, so I think it's safe to assume they did a good job. Comparing lenses, now that's another thing. Eric Welch Grants Pass Daily Courier