Faster autofocus - what's available?

Discussion in 'Nikon' started by RaymondC, Nov 12, 2017.

  1. Just a curious as it is near that festival time and a bit more friends and family gatherings including big groups. Although for my own stuff I shoot on a tripod. With others I am mostly indoors. I routinely shoot at ISO 1600, 1/60, F4. I have a D600 with a old 35-70/2.8. Say I eventually upgrade to a 24-120 F4 AF-S VR, would that be a substantial upgrade? Apart from the D3, D4, D5 what dSLRs are there that provides fast focus and how do they compare to a pro dSLR, I am not into the IQ so much as they are rarely printed.

    The other lenses I used for these events is a 70-200mm F4 AF-S VR.

    Edit. No flash. No where to boucce usually the ceiling is too high. 6 or 8m high and there are group shots anywhere up to 20 or 40 people. They are also quick grab shots.


    Cheers.
     
    Last edited: Nov 12, 2017
  2. In the Nikon world, AF-S lenses provide the fastest AF speed, compared to AF-D (pin drive) lenses like your 35-70/2.8. The actual speed depends on the mass and distance of the elements moved. Canon uses the same inverted rotor principle as Nikon. The AF logic uses both contrast and phase sensors, and relies heavily on predictive focusing for tracking, due to ehe lengthy blackout time between frames. Flagship cameras from both Nikon and Canon place an emphasis on focus speed and tracking.

    Other companies (e.g., Sony) use a combination of rotary and linear motors for focusing, depending on the requirements of a particular lens. These are more agile than AF-S drives, Im;ole AF-S, the focusing rings are not directly connected, but rely on camera logic to translate ring rotation to the lens elements (aka "focus by wire").
     
    Last edited: Nov 12, 2017
  3. Is the D750 the quickest other than flagship cameras? And if so how does it compare to the D3 or D4? Am I right to say the D800/810 are less in the AF department? Do most people just get a moderate level AF camera and adjust to the equipment?
     
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  4. Not having a pile of money, I selected the D7200 and just worked with what I had.
    For the most part AF with the 18-140 AF-S DX lens, works just fine for general stuff and some sports (football, volleyball, tennis)
    Even the screw drive 75-300 AF-D lens AF just fine for me.
     
  5. For an FX camera body, the D750 would be a significant improvement in AF over the D600 and the price is right. The D800 I had a lot of AF struggles with (using f/2 and faster lenses; with f/2.8-f/4 it worked fine), while my D810 works as one would expect. The D750 AF sensor covers a smaller area than the one in the D810 but it has improved low light performance. The D810 has a more substantial buffer than the D750. I guess now that the D810 has been replaced with the D850, it should be possible to find one in the used market.

    DX options include D7200, D7500 and D500.

    As for the lens, if you want fast AF in a wide to short tele zoom, you may want to look for a 2nd hand 24-70/2.8G. The 70-200/4 has pretty good AF and while the 70-200/2.8’s may be a bit faster I would stick to the f/4 and improve things on the camera body side first.
     
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  6. The ability of recent DSLRs and lenses to focus at all in low light amazes me. Just yesterday I was using my D800 and Tamron f/2.8 SP VC 24-70. It found focus in light so dim that I could barely see to compose, and quickly enough that it didn't keep me waiting. (I was using flash for the actual exposure BTW.)

    Anyway, I think any AF-S or compatible lens should focus fast enough that by the time you've composed a shot the focus will be solidly found.

    "Grab shots" of groups of 20 to 40 people sounds like a bit of an oxymoron to me. Just organising that many people into any semblance of a group is going to take way more time than any AF system needs. Maybe unless you're using auto-area AF; in which case you're asking for trouble as the AF point dances around the screen, trying to decide where to focus. Switch to single point AF and all should be well.

    WRT not being able to find a bounce surface for flash: Walls can be used as well as ceilings. Plus if you've pushed the ISO up far enough for available light, even a tall ceiling can provide bounce lighting that's more controllable than ambient.

    At 1600 ISO, a good flash will deliver a GN of around 120 in metres. So even if the 'round trip' bounce distance is 20 metres, you'll still be able to use an aperture of around f/4, that's allowing a loss of 1 stop for reflection losses. However, f/4 almost certainly won't give enough DoF to cover a group of 40 people, since I suspect they won't all be in a single row.
     
    Jochen likes this.
  7. Fundamentally, focusing speed comes down to two things-the ability of the body to identify what is in/out of focus and the ability to physically move the lens elements around to achieve focus.

    With screwdriver lenses, the latter often comes down to the body quality. The F5 and single digit D bodies have HUGE AF motors. With a big, high torque motor on a big lens(I use my 80-200 2.8 as an example since it's the largest screwdriver lens I have) you can actually feel when the camera locks focus.

    AF-S lenses take the variability out of this somewhat, but I still can see a difference in focus speed on big lenses between a low end DSLR like a D70 and even a primitive AF camera like an F4.

    My D800 is my newest camera, and I find that with small lenses-whether screwdriver or AF-S-focus ranges from fast to effectively instantaneous. It does hunt a bit with something like a 50mm 1.4(earliest AF version with the thin focus ring) in low light. On the other hand, all I have to do is tap the shutter button with my 14-24mm and it seem to just go without any delay(and that's a big lens). That lens focuses fast on an F4 as well. The D800 still can't focus the 80-200 as fast as even a D2 series camera.
     
  8. On a new Nikon DX body with a Nikon 35mm f 1.8 G DX lens the AF speed will be so fast you will not need it. And this lens is so sharp and cheap every DX owner ought to have one.
     
  9. Just looking at af-speed, not at available light or IQ or FX vs X: , the AF-p lenses feel much faster then their AF-S counterparts, the AF-P x 18-55 is, thanks to its stepper motor, verry fast an precise on foccussing and almost totally silent as well ..

    Did not get my hans on a FX AF-P 70-300 yet but i hear comparable stories about that one..
     
  10. It will be interesting to see how AF-P fairs in higher end lenses.

    The 18-55s I've played with don't have "real" AF-S in the sense of having ultrasonic ring motor. Rather, they just have a little motor in the lens to crank it back and forth in place of the in-body motor. I don't see that the AF-S system in that lens has any real advantage aside from working on cameras without a built in motor. You still have to manually switch to MF and the front element spins during focusing. I'm not surprised that the AF-P version is faster.

    In general, though, my impression of AF-P vs. AF-S(and the comparable Canon technology-stepper motor focusing is still fairly new to Nikon) is that in some cases it gives up all out focusing speed in trade for being dead silent and almost perfectly smooth. These are both desirable-even AF-S can be loud, and the focusing tends to be a bit "jerky." For still photography, the jerky focus isn't really a detriment and allows the camera to acquire focus faster, but of course isn't so good in video use.
     
  11. I don't use much the mid zoom hence I got a older one. It's mainly with people and groups when I am indoors and under low light.

    Does the D700 have same af module as the D3?

    Group grab shots not bad as you have enough details and a bit more time. Once the 3 or so rows of people are lined up. It's still a 3 or 5 seconds to grab the shot before other people jump in with their phones and tablets and point and shoots.

    Times when the camera struggled was when gifts and certificates were passed to people and occasionally I miss the shot or the subject wasn't in focus. The area is cramped also so the front row of seats is only about 2 meters away from the stage. If group of kids are dancing etc maybe just 1 meter. So at times I get the shot with 1 or 2 row of the audience. Audience is just individual chairs as you do in a seminar room etc. Unless I sit at the front row maybe between in the middle walk path between the left set of seats and the right set of seats and use a 20mm or something.
     
  12. The D3, D700, D3s,D3x,D4, D800, D4s and D810 all have very nearly the same AF module; the D300, D300s, D7100, D7200 and D7500 have the DX version, with a tweak for the D750 that gives somewhat better low-light performance but with the AF points clustered slightly more tightly to the middle of the frame. The AF has been tweaked somewhat over time, but the basic module design has stayed (as far as I know) appoximately the same. It has generally been the case that the single-digit cameras are driven harder (the AF module processor may, for example, be clocked faster - this was particularly noticeable with the D3 vs D300, and the same looks as though it may be true with the D850 vs D5, or it may just be the black-out time difference and different tolerances for the lower-resolution body). The D600, D610, D7000 and Df have an AF module that is clearly a step behind in capability. The new AF module in the D5, D500 and D850 is clearly another step forward (so if you want to pay for the best AF currently available, it's in these three bodies).

    The single-digit bodies, in addition to bigger AF motors, generally provide a higher voltage to the camera mount - not all lenses use this, but some do. The battery grip on some bodies (certainly the D700) also allows a higher voltage to be passed through to the lens mount.

    AF performance comes down to four things: the AF electronic subsystem (why the D610 won't keep up with a D5 with the same AF-S lens), the aperture of the lens driving it (why slower lenses typically focus more slowly, and - because the AF system is tuned for accuracy - why the f/1.4 lenses are often slower than the f/1.8 ones), the power of the drive (why an F5 can, I suspect, still out-focus a D7100 given an original 80-200 f/2.8 AF), and, as Ed said, how much weight the AF system has to move how far; most big superteles have very lightweight and fast focussing groups, whereas in some lenses, almost the entire lens has to move; macro lenses are often very slow to focus because they have such long travel. AF-S isn't inherently faster, but it does mean the motor can be sized and positioned appropriately for the lens - more an issue for the big supertelephotos.

    If you don't care so much about aperture, the 28-80 f/3.3-5.6G is so light that it's literally taped together and will focus scarily fast on an F5 (and frankly almost anything). The optics are way behind the f/2.8 lenses, though - but it would be a very cheap experiment.

    Which AF settings are you using? Set to single point (or perhaps d9) and with the AF point hovering over what you want in focus, I'd hope the camera can keep up; it might struggle a little more with 3D tracking. If you shoot slightly wide so you can re-crop in post so you can keep to a central AF point, I'd not expect the camera to be the limiting factor if it's set right. Not that I'd claim to be an expert in these circumstances, but I want to check you're on optimal settings before resorting to a new body or lens.
     
  13. I have heard this mentioned several times, and I don't doubt that there's a lot of truth to it.

    The F5 runs on 8 AA cells, or 12V. I think the NiMH batteries for the D1 series are 14.4V.

    I've never owned a D700, but the popular battery that I suspect was used in it was the EN-EL3(e), which is 7.4V. With an MB-D10 grip on my D300(which is the same grip the D700 and several other cameras take) and an EN-EL4 battery(D2 and D3 series) in it, the camera absolutely flies. It will run at 8fps, and the autofocus FEELS a lot faster both with AF-S and screwdriver lenses. The EN-EL4 is 11.1V.

    I've not had a chance to use an F6 out in the field, but the default configuration(no battery grip) is two CR123As. This is 6V, and both the AF and motor feel a bit pokey compared to the F5.

    Also, I know that back in the days detachable motor drives on film cameras, the motor would generally run faster on Ni-Cds than on alkalines. This was attributed to their lower internal resistance. The New F-1, for example, can "only" do 4.5fps on 12 AAs, while with the high speed Ni-Cd pack(also 12 AA sized batteries) could manage 5 fps. Granted that became irrelevant later-the F5 can rip through as much film as you want at 8fps on 8 AAs.

    Something else worth mentioning in regard to screwdriver lenses is how they're geared. From memory, I think that when I bothered to count my 50mm 1.4(again, first gen with the thin focus ring) is either 4.5 or 5 turns lock to lock. That makes it easy for early low end cameras to turn, and also allows finer control over the focus, but the trade off is speed. I've never counted the turns on my 105mm AF-D Micro, but I wouldn't be surprised if it's 10 turns-I don't really care as I often manually focus the lens anyway, and when I do use it in AF I'll trade speed for accuracy. By contrast, I have a 70-210 that I think is 3.5-4.5. It's a typical 90s high end consumer zoom, which means that it's built more solidly than a lot of pro zooms today :) . In any case, the gearing on it is crazy low-maybe 1.5 or 2 turns-and an F5, D1, or D2 can slam it into focus almost instantaneously.
     
  14. OK ... the D3, D4, D5 and the D500 are better but would it still be challenging? Obviously I need to upgrade to a quicker focussing lens right but is the D600 still able to do the job in your view?

    With the better cameras I could maybe do with a F4 lens but no slower.

    I checked the shots that were more affected it was ISO 1600, F2.8, 1/80.

    Yes, maybe I could had used AF-C as well but the 35-70mm was hunting back and forth and it was clearly out of focus if the shutter released.

    Baptism as they got in the pool and got up and walked off, I wanted the shot when they got up and turned around and just before they walk off. Wearing black clothing. I was right up to the pool and using maybe a 40mm focal length.

    I was thinking about it and if that is too hard for the equipment, maybe I should had a bit more to the other side and faced the person and get the shot as they just got out of the water and not wait until they turned around.
     
  15. Single point AF (centre) with AF-S (not dynamic). In hindsight I should hav used AF-C but with the 35-70mm the lens was clearly way out of focus and hunting back and forth.

    Maybe I should had stood at the baptism pool a bit to the other side so I was facing more to the person as he or she got out of the water and not wait until they turned around. If I did wait till they turned around and just before they walked off as I did on the day, would a flagship camera still be challenging in that situation?
     
  16. Hunting is often a sign of insufficient light and/or contrast for the camera to be able to lock focus. Those annoying beacons on the front of the camera(which I always turn off) do theoretically help if you're close enough. IMO, the "grid" from a Speedlight is much better and less distracting, but I'd still hate to have that flashing during a baptism. I'm pretty sure-either through the camera or the custom setting on the Speedlight-that the grid can be activated without the flash firing but I'd have to look up how to do it.
     
  17. That's EV 5 if I am not mistaken. Not that dark at all and certainly not dark enough for any Nikon DSLR to have trouble focusing. Or where you using flash m(in which case the parameters aren't really indicative of the light level)?
     
  18. I did think of the speedlight's red beam afterwards. There is also the body'a AF assist light. I am still not sure if I should use them though. The couple of people who walk into the pool and be beamed with a red or white light (?!).

    Yes on the speedlight's setup panel you can set the red light to be on without the flash firing :)
     
  19. I consider the beacon on the front to be a nuisance, and it's one of the first things I turn off when I get a new camera. If anything, I think they've become brighter over the years. To me, they're blindingly distracting and still might not help that much.

    The red grid, to me, is much, much better. Not only is it less bright, but it also gives the AF sensors a defined line on which to focus.
     
  20. I think you are using the wrong AF settings on your D600. If people are moving just a bit, AF-S (the setting, not the lens type) is not going to cut it. On my D750, switching to AF-C, and to 3D area mode made a huge difference compared to single point AF-S, which I was used to from my D70. I don't think the screwdriver lens is really the limitation. I have had good results at the Chicago air show with my 80-200/2.8 AF-D, with the blue devils (or is it angels?) zooming by so close a single plane would fill the whole image. Before investing in a new body just for the autofocus - the D600 IQ should be as good as the D750, so there's no reason to upgrade for that - I'd practice with different AF mode and area settings on the D600. If the lighting is very bad, then yes, you could gain from a D750. But as stated in an earlier reply, you are not that low in EV, so the D600 AF should work ok with your 35-70/2.8 AF-D lens.
     

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