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Alex D80
06-30-2007, 04:16 PM
This sounds like a dumb question, but you know, if I don't ask it, I will stay dumb regarding this matter; so here it goes.

What is the difference between AF and AF-S?

Are AF-S silent/faster than AF? I do see that they are more expensive; so better construction? Better glass? Sharper images?

Again, sorry for my ignorance, but hey, I tried reading and finding some information about it and couldn't in the Nikon forum and in the leses review it is pretty vague since Nikon there are only about 5 lenses reviewed.

r3g
06-30-2007, 05:39 PM
Not a dumb question at all. AF lenses use the cameras internal focus motor (if it has one), AF-S lenses have their own focus motor inside the lens. If you put a AF-S lens on a body that has its own focus motor the lenses motor is used. I believe the AF-S motor is faster then Nikons in body motor but dont quote me on that.

Alex D80
06-30-2007, 06:14 PM
Not a dumb question at all. AF lenses use the cameras internal focus motor (if it has one), AF-S lenses have their own focus motor inside the lens. If you put a AF-S lens on a body that has its own focus motor the lenses motor is used. I believe the AF-S motor is faster then Nikons in body motor but dont quote me on that.

So my D80 uses the internal motor or lens motor? Which is faster? Quieter? Which one is more accurate?

I am to assume that to my questions, do to price, the AF-S are faster and quieter. But again, dumb questions, but unless I ask them, I will stay dumb!

r3g
06-30-2007, 06:34 PM
To my knowledge AF-S Lenses are faster and quieter. As far as accuracy goes though, I think that depends on what lens vs what body.

achuang
06-30-2007, 06:41 PM
In general AF-S lenses are faster and quieter although there are some exceptions like the consumer AF-S lenses like 18-55, 55-200 although they claim to be AF-S they aren't true AF-S which allows full time manual focus. You'll notice in the back of the lens with the lens contacts. True AF-S lenses have 10 contacts, the cheaper AF-S lenses have less. And the older AF or AFD lenses have only 5 contacts. If a lens has a focus motor in the body then it will use the lens motor to focus regardless whether the body has a focus motor. AF or AFD lenses need to use the motor in the body of the camera as they do not have their own motor. These types of lenses must be manually focused on cameras like D40(x) since they have no motor in the body.

I say generally AFs lenses focus faster because they do, but AFD lenses such as the 50, or 85mm prime lenses focus faster even without a lens motor simply because they have a larger aperture so it gives the body more light to autofocus with, and the fact that there's not much glass to move as they are small lenses.

K1W1
06-30-2007, 06:41 PM
So my D80 uses the internal motor or lens motor? Which is faster? Quieter? Which one is more accurate?

Your D80 will use it's internal focus motor with standard lenses and let the lens use it's motor it the lens has one.
Generally AF-S lenses focus faster
Generally AF-S lenses are quieter
Generally AF-S motors are more accurate
With the exception of the 55-200VR (and maybe others but I'm sure Coldrain will point out the negatives) you can also manually focus AF-S lenses at any time just by turning the focus ring. With a non AF-S lens you need to select either manual or auto focus using a button or switch on the lens or camera body.

wh0128
06-30-2007, 06:53 PM
For some reason I don't understand why Nikon would put an AF-S on the 18-55 if it really wasn't an AF-S, like achuang says.

Anyways, yes an AF-S will focus quicker,quieter, and alot smoother than lets say an AF-D. Take for example the 80-200 f/2.8 AF-D compared to the same lens but AF-S which also weighs a lot more, is longer, and focuses much better than the AF-D version. But not all AF-D or AF lenses are useless.

dxrocnxj
06-30-2007, 11:46 PM
so the af-s leanses are the ones that work the d40?
or do both work just as well?

achuang
07-01-2007, 12:27 AM
that's correct, AF-S lenses are the ones that work with the D40. AF or AFD lenses won't autofocus. Sigma HSM lenses also autofocus on the D40. They're the equivalent of AF-S.

tcadwall
07-02-2007, 06:37 AM
For some reason I don't understand why Nikon would put an AF-S on the 18-55 if it really wasn't an AF-S, like achuang says.

This is just another technicality. AF-S is supposed to designate not only that the lens has internal focusing, but that it is also instantly over-rideable by turning the focus ring. However, Nikon neglected that capability in just a couple of lenses (it is probably cheaper to have a design that doesn't have an instant clutch mechanism to allow it to be over-ridden). So it appears the Nikon re-thought the "AF-S" designation for some of their kit lenses, in order to keep the internal focus motor. They probably knew that they were going to have future bodies without motors when they designed these lenses.

K1W1
07-02-2007, 07:25 AM
AF-S is supposed to designate not only that the lens has internal focusing, but that it is also instantly over-rideable by turning the focus ring.

I wonder about that. Did Nikon actually ever come out publicly and say that? It may be that everybody assumes that is the case because all AF-S lenses until recently have had that feature. But until recently all AF-S lenses have been at the higher end of the scale, now they are drifting down to consumer class.
It may simply be that the S designates that the lens has a Silent Wave Motor, no more and no less.

tcadwall
07-02-2007, 07:58 AM
It may simply be that the S designates that the lens has a Silent Wave Motor, no more and no less
This is probably more correct, but until the time of the mentioned lenses, I believe all AF-S lenses had automatic override, which kinda made the user world believe it to be synonymous.

K1W1
07-02-2007, 04:37 PM
I believe all AF-S lenses had automatic override, which kinda made the user world believe it to be synonymous.

I agree I think everybody assumed that because a feature was there is was automatically part of the set defined by AF-S. I guess Nikon actually had other ideas.
Now that AF-S and VR will be incorporated in all or almost all new lenses (that is my thoughts) we may see two classes. The Pro or semi Pro lens with the manual focus override and the consumer lens with a lighter construction and no manual override.

tcadwall
07-03-2007, 05:05 AM
That is the weird thing... I don't consider the 18-200mm VR a pro lens... and there are others as well, that have AF-S, aren't pro glass, and still have the auto override.

On a separate note, I think the Tamron 90mm (which I am interested in) has an override that is more simple than the switch, you just pull (or push, can't remember) on the barrel to engage the clutch. So you could af, and pull the barrel, and in one movement, fine-tune the focus. One extra step, but very close to the auto-override - no fumbling for the correct switch - VR models have at least 2 switches.

mistrg45
07-01-2008, 01:51 PM
does the AF lenses work with this body?

arejaywhy
09-13-2012, 05:21 AM
I just googled that very same question (af vs. af-s) and found this site and your answer.
Thanks so much for your answer. I'm going to keep coming to this site for info. etc. Thanks again.

Dread Pirate Roberts
09-13-2012, 07:21 AM
Good stuff, welcome to DCResource and glad the site helped