whitewolfowner

They are introducing them on the kit lens class, so that should tell you something. From what I read, I'm assuming it's to get a cheaper way to have a silent motor so you can auto focus when videoing. The AF-S lens motors on the kit class lenses are slow and noisy; not exactly what they claim to be. The S is supposed to stand for speed and silent; neither of which they are.

Apaflo Loc: Anchorage, Alaska

You have repeatedly said there are two different definitions of dB. That 10 dB for voltage is different than 10 dB for power.

The fact is, dB is a power ratio, period. It can be calculated with voltage, but it is still a power ratio. Either way, it is 10 dB. The same 10 dB. There is only one version. One definition.

Now the question is just one of if you are lying to weasel out of all you've said in the past and actually did finally understand that chart you just cited, or if not.

A few of your previous statements:

"A ratio of 10 is either 10 dB or 20 dB. No matter how you look at it,
that's two different versions of dB."
http://www.uglyhedgehog.com/t-388641-3.html#6529420

In fact that is one version of dB.

"The table is clear. A power ratio of 10 is represented by
10 dB (the classic definition) but the amplitude ratio of 10
is 20 dB. That's two definitions."
http://www.uglyhedgehog.com/t-391589-3.html#6591983

No, just one definition of dB.

"In P=VI, replace I with V/R and you get P=(V^2)/R? Did you ever
see that one? It explains why dB that applies to power (P) is
different than the one that applied to amplitude (E)."
http://www.uglyhedgehog.com/t-391589-3.html#6592353

Just one definition that applies to everything.

"There is ambiguity about which version of dB should be used ..."
http://www.uglyhedgehog.com/t-391589-3.html#6592616

There is only one version of dB.

Regardless, you probably should never get into debates about electronics of any kind.

selmslie Loc: Fernandina Beach, FL, USA

I take back what I said. You are not intelligent enough to understand the concept of dB. You don't understand the article I pointed you to. As long as your mind is closed you never will be.

Go find someone less intelligent than you to argue with, if you can. I'm done with trying to teach you.

Apaflo Loc: Anchorage, Alaska

Less intelligent? Would that be "The table is clear. A power ratio of 10 is represented by 10 dB (the classic definition) but the amplitude ratio of 10 is 20 dB. That's two definitions."
That is just one definition. Just one. Go ask any working electronics engineer!

selmslie Loc: Fernandina Beach, FL, USA

Yes, and maybe someone who can't read any better than you can either.

Try reading the article with an open mind.

Get back to the subject of the thread. This is getting silly.

jrh1354 Loc: Dayton, Ohio

OK, guys, that's enough for now. The challenge has been made and accepted. Please meet in the attic at a time convenient to both for the duel. Your choice of weapons!

And thanks to all the posters for a really good discussion - though I'm still not 100% sure what the difference is between AF-S and AF-P. Maybe a Nikon engineer or tech could enlighten us.

Cheers

whitewolfowner

Basically, the difference between the AF-S and AF-P lenses is that the AF-P has a quit motor for the auto focusing on the kit lenses. Really, that's all that's it to know unless you are into technology and want a pure technical answer; then look up the two type of motors. The P lens is a cheaper technology motor that achieves the purpose to do the job, auto focusing silently so it's not heard on the video when operating.