Nikon DSLR Body Auto-focus Motor Quality

Discussion in 'Nikon' started by mark_fukui, Nov 4, 2010.

  1. Hi guys,
    I realize that models, with the D50 as the exception, above the D90 have an auto-focus motor built into the camera body, and models below do not. I was wondering if the auto-focus motor differed in quality lets say from the D50 to the D90 to the D3? It would makes sense that there is some small difference that would favor the D3, but is it a large difference? I am just wondering because i would like to know that if the motor in the D50 would negatively effect auto-focus speed for a demanding environment such as sports? As far as i am concerned the auto-focus speed, which is determined by the built in motor depending on what lens one is using is going to be a tad faster as you go up the chain. For example D50
  2. I'm thinking that the difference between the D300's (for example) AF brains (and sensors, of which there are many more) and that of the D50's will make far more of a difference in AF responsiveness and accuracy than will the difference between their mechanical AF systems.
  3. Nikon does put smaller and less powerful motors in its less expensive bodies, when it puts them in at all. I agree with Matt that differences in processing power play an important role in AF speed differences.
    However, the effect of the different motor sizes vary with lenses. A relatively heavy lens like the Nikon 80-200mm f/2.8 (non-S, without its own motor) is very slow on a D50, not so bad on, say, a D300. Its heavy elements and mechanical components make big demands on the motor. There is not so much difference in the AF speed between these bodies when a 50mm f/1.4 is mounted.
    With small, light lenses, then, processing power makes the biggest difference. With heavy lenses, the in-camera motor makes the biggest difference. That is why Nikon's going to motorized lenses, and (sigh) Canon's having them all along (for its present lens mount) makes sense. The motor can be sized according to the demands that will be put on it.
  4. the pro models have stronger focus motors and better AF modules, along with 4-channel output for fast focus lock and near instantaneous capture. they are built for speed and also built for sports.
    your question, whether a d50 would negatively affect AF speed for sports, is phrased somewhat awkwardly. by that i mean, if you are asking, would a d200, d300, d2x, d3, d3s, or D3x be faster in general, the answer is yes. and, if you are asking, would a d50 focus faster with an AF-S or HSM lens over a screwdrive or micromotor lens, assuming we're comparing apples to apples, the answer is also yes.
    one indication of processor speed is the frames per second rate. the d50 is one of nikon's slower bodies, at 2.5fps. so it's no speed demon.
    but like hector says, lenses are the other half of the equation. a 50/1.8 has a very short focus throw. it will AF faster than some consumer-type AF-S lenses, even on a d50, because it doesnt have very far to travel to acquire, lock and maintain focus across the focal path.
    interestingly, some screw-drive lenses are faster than micromotors, even on a low-end body. and short primes will focus faster than some AF-S zooms. with a d50, you can use non AF-S lenses and still AF, so that's something to keep in mind if you are shooting sports.
    similarly, an 18-200 will focus more slowly than an 18-70 or 18-55, especially if you are going from one end of the zoom range to the other. they all have consumer-type AF-S, but the focus throw of the 18-200 is much longer. a nikon pro lens like the 70-200 or 24-70, will have a faster AF-S motor than a kit lens. i think sigma also puts better HSM motors in its upper-echelon lenses than some of its lower-end glass.
  5. My 300 f4 AF screwdrive lens is pretty good on my D90, but my 70-200 f2.8 VR2 smokes it. I swapped lenses once with a guy at the races who had a D3 and a 70-200 f2.8 VR1. He thought the 300 f4 was pretty fast. It may be faster on the D3.
    Given how fast the 70-200 VR2 is, I probably will use the 300 f4 screwdrive only on very rare occasion now.
    Eric -- what does "4-channel output" mean?
  6. The more money you spend at any point in time, the better the autofocus algorithm and the more powerful the motor. In the past I have used the old 'screwdriver' 300mm Nikon on a D70 and also on a D2H. Absolutely no comparison! Not even close. Not only was the D2H far better at acquiring and staying on birds in flight, but the brute force of the motor was truly impressive.
  7. There are plenty of differences among the AF motors on Nikon bodies. I found the one on the D80/D90 series slow and underpowered, the D300 has a much better one. The D2 and the D3 both have a nice, fine-tuned motor you can tell it was engineered with precision in mind, very good torque to.
    To me the most awful of them all is the one on the N90 series, slow and so noisy I rather focus manually when using that camera. The one on the F5 though still has the most torque in my perception.
  8. Eric -- what does "4-channel output" mean?
    it basically means double the processing speed as 2-channel output*. this is something nikon put in the d200, d300, d2, and d3series, which you won't find in d90,80,70,60,50,40, etc. it doesnt really come into play unless you are shooting fast action at high frame rates. but it's a reason why the pro nikons are faster than entry-level models.
    *i'm sure there's a highly-technical explanation available on nikon's website, but i'm too lazy to look it up.
  9. Thanks for the input. I was considering buying the nikon 80-200mm f2.8 along with a used D50; but, i am starting to shy away from the idea especially since i wanted to use it for sports. I really want to shoot sports; I can't find a very cost effective way to do it. I might settle for the sigma 24-70mm f2.8 hsm, but now i am getting off topic. The explanations really help. I couldn't find a high quality response like this from google. :D
  10. Is it April 1st????
    With the exception of the old F3AF system, all Nikon lenses have internal motors that control focus.
    There's no focus motor in the camera body.
    - Leigh
  11. I explored this very thing with my D70s vs a friends D200. The D200 drives the screw drive (non-AFS) lenses with greater authority. Between the higher torque motor and improved AF electronics of the D200, I felt like I couldn't miss a shot.
    My question now is, does the D7000 have the higher torque motor. I asked Nikon about this and they just referred me to the info on their web site which says nothing about it.
  12. Leigh: that's just plain factually incorrect. Nikon makes many bodies, including brand new ones, that have focus motors in the body, coupled to a driver for the screw-driven mechanisms in non-AF-S (motorless) lenses.
  13. Well, Matt,
    Perhaps you can explain why Nikon makes such a big deal about the Silent Wave Motors in their lenses, but says not one word about motors in the bodies.
    For example, in the D90 manual, the only reference to the autofocus Silent Wave Motor (or to any motor) is on page 273, in the description of the 18-105mm kit lens.
    The D90 manual can be downloaded here
    If there's a reference to in-body focus motors, kindly provide the document URL and page number.
    - Leigh
  14. Leigh: I own multiple Nikon DSLR bodies with screw-drive AF motors. I promise. AF-S lenses are great, and they're making more and more of them now - and the more the merrier. But there are plenty of people using newly purchased D700's, D3's, D300's, the new D7000 (as well as the older D50, D70, D80, D90) with screw-drive lenses like the 85/1.4, or the 60/2.8 micro and dozens of others. Really! I promise. Only Nikon's entry-level bodies (like the D40, D3000, D60, D5000, D3100) are missing this feature.
  15. Yes Leigh. Well they would prefer you to shell out on their newer lenses, wouldn't they?
    Its always about backwards compatibility. With the exception of the lowest spec bodies, all the other DSLRs have what we call a "screwdriver", so that the older AF and AF D lenses can still use their AF capability on current bodies. This is the edge Nikon has over Canon....investment protection.
    The newer lenses have SW motors in the lens itself and it makes them fat and heavy. When you mount either type of AF lens, the body talks to the lens and then knows which AF system to use.
    I had a D300 and an older 70-210 AF D lens. This lens smoked on the D300. Its focus speed was instantantaneous. It was the same when used on my F4. In many ways the older AF screwdriver lenses can be almost as good as the newer ones. I paid $150 for the 70-210 and its a fraction the size of the current 80-200.
  16. Leigh,
    Yep. Listen to Matt. Every Nikon Film camera from the F3AF to the F4, F5, and F6 ALL have in camera focus motors. All the Digital SLRs from the D100, D200, D300, and the D70, D80, D90 and now the D7000 have in camera focus motors.Of course the D1, D2, and D3 series all have a motor too.
    Here is a link to the Nikon Wide angle lens page;
    ONLY the lenses that SAY , AF-S have the motor in the lens. That's 3 out of 10.
    Here is the "Normal" lens page.
    Only 1 out of 3 are AF-S
    3 out of 8 in the telephoto page
    Get the idea ? AF-S is very often seen in the consumer and zoom pages, but not as much in the fixed focal length pages.
  17. A discussion of the Silent Wave Motor (which is in the lens):
    And from the discussion in the Nikkor Lens Glossary at
    "AF-S NIKKOR lenses feature Nikon’s SWM which converts “traveling waves” into rotational energy to focus the optics. This enables high-speed autofocusing that’s extremely accurate and super quiet."
    - Leigh
  18. Dear Leigh B.
    Todays date(i am in Oregon) is November fourth. Recently made lenses do not have the AF-S, but older lenses nikon 80-200 f2.8 AF do not. That was one of the lenses i was considering. Also the nikon 50mm f1.8D does not have an auto-focus motor. By saying the F3 AF system are you implying that all AF lenses do not have an internal focus motor? If so you have correctly defined AF and AF-S. AF does not have an internal auto-focus motor, while the AF-S lenses have an internal auto-focus motor. I am not sure what you are implying with F3AF. I looked it up on the internet and it gave me an old nikon body. Could you please specify what you mean in that statement.
    Have a good day, Mark
  19. OK. My error. Apologies to the masses.
    I didn't catch the distinction between the AF and AF-S lenses. My comments relate to the AF-S series.
    The F3AF that I mentioned was Nikon's first attempt at autofocus, released in 1983 IIRC. Those lenses are not compatible with any later Nikon system that I know of.
    - Leigh
  20. Nikon boddies that have a built in motor will have a little tab if you look at it from the front it is located at 7 o'clock.
  21. Leigh, just look in the owners manuals (they can be downloaded from Nikon support) under "Technical Notes" and "Compatible Lenses" and you will see what lens are compatible with what cameras. It will tell you what will or will not work - autofocus, metering, etc.
    What everyone is saying true though - the D50, D70, D80 and up have a mechanical drive for the non-AF-S lenses. The D3000, 3100, D40, D40X, D60 do not. You can use the non-AF-S lenses on them but you will have to manually focus them.
  22. Leigh,
    No worries. Main thing is we clear everything up. Don't want yeah running around not knowing about AF and AF-S. Photography requires a lot of artistic skill; but, a little research goes a long way.
  23. Perhaps you can explain why Nikon makes such a big deal about the Silent Wave Motors in their lenses, but says not one word about motors in the bodies.
    actually, this is not true. nikon literature will occasionally tout things like the 4-channel processor in the D200 or the multicam3500 AF module in the d300/700/3. but in general the SWM is a big part of nikon's marketing push, which is aimed more at entry-level users--by far the biggest market segment for DSLRs--not seasoned or experienced photographers.
    also, it's generally helpful not to believe every word of marketing-speak.
    but this much i know: every nikon DSLR prior to the d40 had a focus motor. i remember a lot of discussions from three years ago which centered around the then-available choices between D40 and D80, and general consensus was that the d80's in-camera motor was a better feature, since it allowed use of non-AF-S lenses, and that the d40 was limiting in this regard.
    of course, since then, nikon has released a lot more AF-S lenses, such as the 35/1.8, which make this less of an issue for owners of cameras like the D60, D3000, D5000, and now D3100, and 3rd-party manufacturers have been putting motors in a lot of their glass, either micromotors or AF-S equivalent. yet some limitations persist (which is why the d90 and d7000 are great cameras for their market segments, because of their compatibility with a wide array of lenses, as well as their feature set.)
    in real-world terms, lens compatibility issues might push an entry-level body owner to the nikon 10-24 or sigma 10-20 instead of the optically-superior tokina 11-16, or result in buying the $450 50/1.4 instead of the $120 50/1.8.
  24. What a bumpy track this has been.....AF speed is dependent not just on what mechanical system is used, but also the AF firmware working in the camera too. Some AF lenses are fast focussing, some are slow, Some take only half a turn of the screwdriver some, a full turn.
    Its the same with AF-S lenses. An AF-S lenses will focus faster on a D3 than on a consumer body. Black and white comparisons are not valid here.
    Look at those reviewers who aren't afraid to be opinionated like Thom and Bjorn. Even KR rips into Nikon more now if its warranted.
  25. My old Nikon D1h will focus my old screwdriver Tamron 28-75 2.8 much faster than my D80. The motor in the D1h is so much more powerful it's not even funny. I would guess using an old 80-200 2.8 (without silent wave) would show even more differences as the lens elements are much bigger and heavier.
  26. The motor in my F5 (when using fresh lithium cells) is so powerful it tests my cheaper lenses to the max. A 50mm f1.8 AF-D jerks into focus - the spinning lens barrel is so rapid it is almost not visible.

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