Lens Autofocus Speeds

Fozzyffp

So im patiently waiting for my D500 to ship. This delay is making me think about upgrading a lens or two to match it. Now ive used some nikon dslr/lens combos where as soon as you tap to auto focus button, boom the lens snaps everything into focus. Other lens/camera combos slowly or moderatly adjust the focus until the image is crisp.

Currently i have a D5100, 18-300mm 3.5-5.6, sigma 8-16mm, and the 35mm 1.8

Now im curious if the camera is holding the lenses back, or are the lenses just not that fast at focusing? i know they are zooms and blah blah blah...

What Id really like to know is if anyone has a list or knows of lenses that have the instantaneous autofocus? ive tried googleing, and searching the usual sites for input but found no lists. any input here is appreciated.

-Matt

spraynpray

I don't know of a list that ranks lenses by AF speed as such, but if you have pre-ordered a D500 and can keep your D5100 to compare it to, you will soon(ish) have the tools you need to make the comparison as to whether the body influences the focus speed most, or the lens, vice-versa or a bit of both. From your list, I would have thought the 35 is quick, the 18-300 is slow and the 8-16 is medium - yes? I would also expect the D500 to have snappier focus than the now old nearer entry level D5100.

Nikoniser

OK so there are 3 stages that influence Speed of focus, I will give them to you in order of what a happens when you press the autofocus button.

I will compare a D3200 ( entry ) , and D7100 (prosumer) and a D810 (pro - D810 also is almost identical in performance to a d4 )

I would expect a D5/D500 to perform better than a D810.

1. Camera : Aquire autofocus lock. This is how fast the camera is to aquire an initial lock and tell the lens to move to that position. This is dependant on how sensitive the camera is to contrast changes, a figure you can use to estimate this is the low light EV rating, typically -2 to +19 - use the - figure, larger is better, scales logarithmically so -2 is twice as good as -1

The lens also affects this rating - above f2.8, each stop of light loss slows the aquistion sensitivity down by half.

In bright light, on a high contrast target, initial lock is very similar between cameras

D3200 -slow
D7100 - fast
D810 -very fast

2. The camera then tells the lens to move to the focus point.
AF-S lenses - this is almost totally dependent on the focus motor in the lens. the camera has a small effect, but not much. Pro ( f2.8 ) zooms are *much* faster than consumer f5.6 lenses, and the smaller the zoom range typically the less the focus elements have to move so faster. Primes are an interesting case... the f1.4 primes typically have to be very precise as focal plane is so tight and and often focus slower than pro zooms. The prime f2.8 and f4 telephotos are the fastest to focus.

The one exception seems to be Macro primes they can be very slow to focus if taken from one end of the focus scale to the other, and the pro bodies do this much faster. but typically respond very very quickly to small changes in focus distance and here the camera bodies are very similar.

Your 35mm 1.8 is somewhere between the f1.4 lenses and the pro f2.8 zooms.

Note that Canon cheaps out on the batteries and that Canon consumer bodies do autofocus slower with EF lenses than the pro bodies.

AF "screw" type lenses - totally dependant on the body and the battery.

D7100 slowest, followed by D810. Adding a grip speeds both up. Older Nikon F5s also focus very fast with screw lenses.

Interestingly, the "short" AF screw fast primes have quicker initial focus movement than the AF-S primes.

3. The lens completes its primary movement, and focus is confirmed - this is where you see "hunting" - which a delay before final focus lock is confirmed.

This scales with the EV rating of the Cameras combined with the motor rating of the lens combined with the contrast and light level of the subject.

The Pro AF-S f2.8 zooms on the D810 snap to focus lock instantly, in AF-C mode you then hear a fast slight clicking as very tiny tracking adjustments are made.

The Pro AF-S f2.8 zooms on the D3200 snap to focus lock but then have slower clicks and sometimes hunt a little in lower light.

The AF lenses seem to snap very very fast but then you hear a little back and forth adjustment before final focus lock - it seems the "lash" of the mechanical movement reduces speed and accuracy here. They also seem to track movement not quite as well as the AF-S lenses. One thing I do like is the physical feel of focus - you can feel the torque in your hand as the lens focuses on the pro body and get great confirmation when its in focus, haptics is the phrase.

The consumer lenses 5.6 lenses on the pro bodies don't hunt in good light, but as they give less light to the autofocus system, they are more prone to hunting in very low light, however the hunt range is smaller.

The consumer bodies + the AF-S f5.6 consumer lenses, go slowly to initial focus, and then give a few clicks as they aquire final focus on low contrast subjects much like an AF screw lens on a pro body. They are most prone to hunting and focus issues when the subject starts to move. If I point the D3200 with the kit lens as a low contrast subject, it seems to take two goes to focus, it goes a little over the focus point and then back to the right focus. However even the D3200 and Nikon AF-S lenses have very good performance in good light and on high contrast subjects if there is enough light they straight to focus and stop.

The D7100 is 90% as good as the D810 for final focus lock. It is remarkably good value, and an amazing camera if you don't need the DOF and low light sensor performance that full frame gives.

Note that this is the stage of focus where third party lenses often have problems. I am convinced that there is some nikon secret sauce going on here that no one has decoded. Even the best Sigma pro f2.8 primes struggle here, even in good light.

Nikoniser

In summary,
Cameras have the greatest affect on Low light/low contrast/subject tracking performance.

AF-S lenses have the greatest affect on Focus speed.

Final focus lock *in tricky situations* is a Combination of the lens and the camera.

For your D500 I would reccomend dumping the 28-300 - it is dark, slow to focus, not sharp and has lots of distortion. You can do so much better.

heartyfisher

Nice post @ Nikoniser re: the AF systems. well broken down. Nothing much to add.

Although, his 18-300 probably doesn’t need to be "dumped". Super zooms have lots of compromises IQ wise but they also have unique functionality. I am sure the D500 will be a huge boost in AF speed vs the D5100 for this 18-300 lense.

Even my D7200 is amazing compared to my D7000 and D610 in terms of AF and I expect the D500 would smoke the D7200.

WestEndFoto

I would add that all things being equal, a fast lens focusses slower than a medium lens (say a 1.4 vs a 2.8). The depth of field is narrower, which requires more focus precision.

Fozzyffp

Thanks everyone, especially nikoniser i appreciate the info.

I feel like im in a unique situation, my job requires me to travel almost consistantly, so i try to keep my kit small, only having to carry 2 lenses to do mostly everything is nice. i like the 18-300 because it does everything, but i know it doesn't do it as good as other options. I spend alot of time on the ocean, one second im on the top of the ship trying to shoot a sunset, then a yacht shows up in the distance and boom with a different lens i feel like i would miss shots. The humidity is typically insane and i hate changing lenses outside, with all the salt air and such.

That being said, i do feel limited in some aspects. i love the 8-16 that's not going anywhere. Im open to replacing the 18-300, i may be dreaming a bit but im trying to justify to myself that i would use the 200-500 5.6, I photograph surfers and kitesurfers occasionally, so meh...

What would you all recommend as a solid walk around/do most things lens? Typically I end up in a port, have 4-8 hours to explore, then head back to the ship. I never really know what im going to find ahead of time. I like to be prepared for that Ferrari barreling down the road at me I think at max, i could comfortably carry 3 lens's, but i still dont like the idea of switching things out multiple times a day. i usually walk out with the 18-300 then when i turn around to head back ill switch to the 8-16.

Fozzyffp

also, you have convinced me to at least wait until i have the new camera before i start playing lens roulette. no point rushing, still have a month and a half to go... ha

WestEndFoto

You are fretting to much about changing lenses. Unless you are in a storm, don't worry about it.

BVS

Just a thought, but what about complementing the D500 with something like the new DL24-500? The whole thing with battery and card actually weighs less than your 18-300 lens alone, while at the same time also going both wider and longer. Plus, it'll have excellent AF and FPS (although probably not the buffer) like the D500.

For maximum flexibility, carry both the D500 with one of your shorter lenses attached and the DL24-500. Use the DL for long range and the D500 for wide and mid, and lens changes would be minimal.

If you want to travel extra light (e.g. hiking or something) just carry the DL.

If you know you're going to be mostly in low light just carry the D500.

Ironheart

My goto DX zoom lens kit is 16-80 f/2.8-4 and the 70-300 f/4-5.6. I think the 70-300 is stronger at 300 than the 18-300. I have switched lenses in everything from a hurricane to a sandstorm, and as long as you do it quickly (but not in a hurry), precisely, and with your back to the wind, never had a problem.
I am thinking about upgrading to the 80-400 f/4.5-5.6 though it's not on sale :-w

spraynpray

If I were you @Ironheart, I would get the 200-500 over the 80-400 as the 70-300 VR is not at its best at the long end. If you are feeling flush, the 70-200 F4 would be an ideal partner to the 200-500 because the IQ is better and the VR is waaay better than the old 70-300 VR.

Ironheart

The 70-300 isn't awesome at the long end, but it isn't horrible either, and it makes a great DX lens The 200-500 isn't really what I need, since I like the range of the 70-300 and the overlap with the 16-80. The 80-400 solves that problem, the 70-200 isn't long enough, and it's a beast that I don't need/want on a DX system. What I'm sayin' is that a two lens kit gives better options than a 18-300 superzoom.

Edit: I just saw you were referring to the 70-200 f/4, which will be more on par with the 70-300 weight wise, but for my purposes still not long enough, and for @Fozzyffp it seems he wants at least 300, perhaps the 200-500 works.

spraynpray

I only used my 70-300 on DX so we are talking about the same use. Ian (Dissent) has a good one which is very sharp to 300 but mine was more typical and was great up to 240 then 'meh' after that. The 200 f4 is one of the best VFM lenses Nikon do IMHO as the VR is like glue and the IQ even wide open is superb.

My point to you was, if you bought the 200-500, you would only have to use it when you knew you were going out doing long shots so you would still have a two lens kit with good overlap most of the time. I find that I never take all my gear out as the weight spoils the day for me. I'll even leave stuff in the car rather than carry it if the weather isn't too hot.

Carrying up to three (usually two) lenses is enough for me (I am not superman). When it does get too much, I will make a proper large gain and go MFT or even 1". Even just the D750 and 24-120 is intrusive on holiday so a J5 would do for that but you never know when that award winning shot is going to present itself so I end up lugging three lenses and an FX...

Go on, you know you want a 200-500...

Ironheart

Damn. They aren't on sale either...

WestEndFoto

spraynpray said:

Carrying up to three (usually two) lenses is enough for me (I am not superman). When it does, I will make a proper large gain and go MFT or even 1". Even just the D750 and 24-120 is intrusive on holiday so a J5 would do for that but you never know when that award winning shot is going to present itself so I end up lugging three lenses and an FX...

Go on, you know you want a 200-500...

I see potentially award winning shots almost everywhere I look, especially on holidays, so I am always lugging around my "FX Bag" and tripod.

tcole1983

My two lens combo is usually my 17-55 and 300 f4, but I always hate to leave my 105 behind and would carry that if I had three lenses. OK I pretty much just always carry all 4 lenses because the 35 f1.8 weighs practically nothing and fits easily anywhere.

My 17-55 is my go to lens if I am taking one. Obviously more limited range than the super zooms, but I know I will get pretty good quality out of that range.

KnockKnock

Hmmm. If I were a D500 user and worked cruise ships, I think I'd get the 16-80 and the 80-400. I've just read a lot about these, and it seems like the 200-500 is just too much of a beast for travel and leaves a lot of mid-telephoto gap to fill.

Google lens switching videos. Is YouTube a verb? YouTube Lens switching videos. I've picked up an excellent, fast technique which makes switching less of a pain. Agree with above, that switching shouldn't cause you issues with moisture as long as you can dry things out overnight. Desert sand is far worse.