I've noticed on several of the AF lenses I have here that some seem to have a very different "gear ratio" for lack of a better term. IOW it takes more turns on the AF coupler to get the same rotation of the focus ring. You can use a small common screwdriver in the coupler and count turns.
Don > -----Original Message----- > From: Joseph Tainter [mailto:[EMAIL PROTECTED] > Sent: Monday, August 23, 2004 8:27 PM > To: pdml > Subject: [Fwd: Autofocus Speed Variation] > > > Repost. I sent this yesterday, but it seems to have disappeared into the > magnetic aether. > > Joe > > -------- Original Message -------- > > > My new puppy, the FA 77, seems a bit slow in autofocusing. So I did the > following test. I took my FA 50 f1.7, FA 31, and FA 77, focused each > manually to its nearest focus point, mounted each on the camera in turn, > turned the focus ring until the autofocus drive engaged, and > autofocused on a tree rather far away (about 100 yards/meters). The FA > 50 f1.7 and FA 31 both snapped into focus quickly, and at about the same > speed. The FA 77 was perceptibly slower. When I remove the lenses and > turn the focus ring by hand, they all seem to have about the same amount > of resistance. > > So, why should this be? > > Joe >
