grahamfourth

I am wondering what contribution a lens plays in limiting autofocusing capabilities. For example, if you have a top-of-the-line camera (e.g. Nikon D5, Canon EOS 1D Mark III) taking BIF images, does the lens itself become the limiting factor in autofocusing? Do some lenses respond more quickly to camera commands than others? If this is correct is it the result of a better mechanism inside the lens? How would you know that lens A is faster focusing than lens B?

As always, everyone's help is very much appreciated.

Ourspolair

The lens mechanism will contribute to the speed of focusing. The only way to know is to try the lens on your equipment. Sometimes identical lenses will have slightly different af speeds, I use the opportunity to test a lens in-store. I do not know of any manufacturers who state the time taken to focus.

CHG_CANON Loc: the Windy City

A professional body like the EOS 1DX III has features that differ from other EOS bodies in regard to AF. Specifically, the 1DX has a dedicated and separate processor for the AF system, or said another way, a processor for running the camera and converting / creating the images and a second processor (computer chip) for driving the AF system. Most cameras have just a single processor that handles all the camera functions. The 1DX also has an integrated battery pack holding two batteries to maximize the juice needed by the camera.

The AF performance of most other cameras will tend to improve with more 'juice' when adding a battery pack.

The AF performance of most other cameras will tend to improve when not using extenders / teleconverters. That is, when you add the extender, you add more glass for the light to travel through to reach the sensor. The image projected onto the sensor is darker, making the AF performance noticeably more (or slightly more) sluggish.

And finally, a wide aperture lens will (almost always) improve the AF performance of the camera by projecting a brighter image onto the sensor. There are exceptions, such as the EF 85mm f/1.2L II or the EF 180mm f/3.5L Macro, two wider aperture lenses that have miserable 'speed' for AF performance. These two lenses are not 'tuned' for speed / AF responsiveness. Sports and wildlife lenses, such as the Great White Red-Ringed prime L lenses, typically feature f/4 or f/2.8 apertures and as well as Canon's cutting edge technology to deliver industry-leading AF performance for all EOS bodies.

RGreenway Loc: Morristown, New Jersey

I have seen that long telephotos with zoom capabilities seem to focus more slowly since the internal glass is heavier perhaps or the autofocus motors are not strong enough. Look for faster focusing in reviews and you will see that the autofocus drive systems are not all the same. The faster ones are called various things, but usually it is apparent which lenses put a priority on this, usually the more expensive ones!

tcthome Loc: NJ

Maybe in a low light scenario. Eg. , f2.8 vs f4 vs 5.6 or, 5.6-7.1. I own the D810 & while I guess the focus system is not as good as the cameras you mention, In lower light, sometimes I wish I had the ability to step down to a lower aperture to let more light in not wanting to go any higher with my ISO at faster shutter speeds for birds in flight. By the way this example is for long lens wildlife only.

RGreenway Loc: Morristown, New Jersey

I agree with tcthome, faster lenses will focus faster in general and a fast lens stopped down will focus a bit slower.

Another reason to go for the fastest lens you can afford and want to carry since faster lenses are also heavier!

uhaas2009

In some cases yes and no..... the Nikon 70-200 2.8 vs 200-500 the 70-200 is a dot stronger one vs 200-500 but the different isn’t that big to worry about it. What throws me of is the shutter lag from 7100 vs 810.
When I use the Tokina lens than a higher end body it does work way better in focusing

Jack 13088 Loc: Central NY

Actually, the reason a wide aperture lens is faster to focus is mostly because it is wider. Phase detection focusing is more sensitive and accurate with a larger baseline.

That is a principal recognized quickly recognized by engineers. Unless, of course, they are blinded by fear of mirrors which can sometimes be cured by appropriate therapy.

Architect1776 Loc: In my mind

Architect1776 Loc: In my mind

In general terms, Yes, the lens is the limiting factor.
For example some sites show a Sony camera AF point jumping rapidly around but the actual photos are not all in focus but many misses. This is because the lens cannot keep up real time with the bouncing AF point.
So get lenses that are Pro action level like Canon 300mm/400mm/600mm Primes the 100-400mm L MII and other lenses are designed to keep up.
I would believe Nikon has similar fast sports lenses.
So if you need a fast responding lens look at what sports people use or those doing birds in flight for lenses.
It is the mechanical aspects of the lens as you say.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

To a large extent focusing speed is a product of the camera body. That said, I have found that the faster the lens, the quicker it seems to acquire focus. So, IMHO, my Sony 600 f4 seems to find focus a nano-second faster than say my Sony 200-600 lens.
That said, a nano second is no that long.
Another focusing factor is the focusing system you choose, for Nikon I have always used Group Auto Focus, on my Sony camera's I like Zone focusing.
I shoot birds in flight so I use the center of the viewfinder to put my focusing system to work.
I also select the focusing distance before I shoot, suppose I am watching a bird build a nest about 50 yards away, I pre focus on something about that distance away, that way my lens does not have to find a distance or hunt first. Or, if the bird is about to take off, I focus on him/her, and as they take flight, I just follow and shoot when the lighting is right.
Below are two different images with two different camera's, the first taken with a Nikon D4s and a Nikon 200-400 lens at f4 using Group Auto Focus, the second is an image taken with a Sony a9, and a 200-600 mm lens using Zone Focusing.
Also, the more you work on technique of panning, the better you will become. I do not use the rear button focus thing, I assign that button to something more important to my style of shooting.
Good luck and keep on shooting until the end.
PS. I first make sure, as I pan, that I have a focus lock, then and only then do I trip the shutter.

imagemeister Loc: mid east Florida

Yes, LENSES can be a significant source of AF capabilities ! Such things as size and weight and number (mass) of the focusing elements, the driving system used, the presence or absence of IS and whether it is turned on or not.

The mass of the focusing elements are larger in faster lenses ( tending to slow AF) - but as mentioned, this is mitigated by the brightness presented to the AF system of the body - so it can be somewhat of a balancing act.

I will say that the focusing of the old Canon 400 5.6 prime is very FAST - no IS and the elements are small and few. The new nano drive of the Canon 70-300 IS II is even faster !
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MountainDave

Both are important but I'd go with the lens being more important. Example: I have a 5D IV and a 77D which costs about 80% less. A few years ago, I bought a 300 4L IS which is a 1990s design. Compared to newer lenses, the AF is slow, noisy and not particularly accurate. With the 5D, it is capable of exquisite images but the "hit" rate with the 77D was so poor I just didn't use the combo. A few months ago, a GAS attack prompted me to buy a 300 2.8L IS II. It performs brilliantly on the 5D IV even under difficult, low contrast conditions. So, I decided to test it with the 77D and was very pleasantly surprised. The combo produced sublime, tack sharp images.

amfoto1 Loc: San Jose, Calif. USA

There are a number of lens-related considerations.

1. The type of focusing motor used in the lens is a key factor. For example, Canon's USM or "ultrasonic" and Nikon's AF-S or "silent wave" motors are the fastest. Their respective STM and AF-P "stepper motor" lenses are fast, too... but not quite as fast as USM. The advantage of stepper motor is that they are quieter and smoother running, so might be better for video work. Another kind of focusing drive in common use is called "micro motor"... those are the slowest type... noisier, too.

Nikon also has used an autofocus system that doesn't use in-lens motors at all... some of their cameras have the drive motor in the body, instead. It's now only the D7000 series and higher that have that. Though fewer every year, there are still some lenses of this type in F-mount (the Micro-Nikkor 200mm f/4, as well as the Tokina 100mm f/2.8 Macro, for example). If used on the Nikon cameras without the in-body AF drive motor (current D3000 and D5000-series), those lenses will be manual focus only.

2. To a point, the lens' max aperture also plays a role in AF performance. Larger apertures let in more light, so there's simply more for the AF system to work with and AF will be able to work in lower lighting conditions. Plus,, while I don't know about other manufacturers, Canon cameras commonly have some AF points that are higher performance with lenses that have f/2.8 and larger max apertures. Usually at least the center AF point in a Canon DSLR is optimized for f/2.8 and faster lenses. (Note: In case you don't know, most modern AF lenses are kept "wide open" until the exact moment of exposure. They only stop down to a smaller aperture momentarily during the actual exposure.)

3. Some lenses are deliberately designed to focus slower. It is common for macro lenses and portrait lenses with exceptionally large apertures (such as f/1.2) to use "long throw" focus mechanisms. This is done because with at macro magnifications or fairly close distances with large lens apertures depth of field can be very, very shallow... demanding more accurate focus. In these cases the lenses are designed to emphasize focus precision over focus speed.

There also may be other design considerations. For example, a lens striving for particularly high focus performance might be designed

4. I have used a number of Canon IS (image stabilized) lenses over the last 20 years and always felt that it helped AF perform better. I have no way of testing and proving this, but it just seems to make sense that a lens would have an easier time focusing upon a stabilized image and subject. However, that doesn't seem to always be the case. Many Nikon shooters choose to turn off VR (vibration reduction) when they want the best AF performance possible, shooting highly active subjects. They feel that Nikkors with VR tend to focus slightly slower when it's enabled. I haven't used those lenses enough to say from experience and there does seem to be some evidence to support this... so I'll take their word for it. Note that there are bound to be some differences between stabilization systems. Canon IS, Nikon VR, Sigma OS, Tamron VC and Sony OSS all do essentially the same thing, but are each systems that have been patented by their manufacturers. I have heard that Sigma OS most closely mimics Canon IS (which was the first system to be implemented, in the mid 1990s). But, again, this is something I can't substantiate because I haven't used Sigma OS equipped lenses enough to say one way or another. I have even less experience with Tamron's VC and Sony's OSS (as in no experience at all).

5. Some lenses today have their own computer chips and firmware. In some cases, the user can access that and adjust how the lens works, including AF performance (speed vs precision). In other cases, the firmware can be updated by the user and that may improve AF performance. Newer lenses may use higher performance computer chips, too.

6. A lens also may have features like a Focus Limiter or a Focus Preset that the user can employ to help focus performance in certain situations. It's not uncommon for telephotos and macro lenses to have a Focus Limiter that can be set so that the AF system only works within a restricted range, speeding up performance. A couple of my Canon lenses also have buttons that I can program to instantly re-establish focus on a certain point. Say I'm shooting a horse and rider going through a course of jumps and decide to focus upon one of the jumps. I can pre-focus and save that info to the lens, then continue focusing and shooting elsewhere, then just press the button to re-focus on that one jump when they reach it. Of course, this can be useful with many sports and wildlife situations... really anywhere that subjects are moving relatively predictably.

7. A really simply thing that can help AF is your choice of lens aperture. When possible, stop down a bit. That will increase depth of field, which in turn covers for minor focus errors. Of course, you have to decide what's most important... if you are shooting in low light or trying to render a strong background blur you may need to use the lens' max aperture. But stopping down from f/2.8 to f/4 or from f/4 to f/5.6 when you can will help assure a higher percentage of in-focus, usable shots.

Familiarity with your gear and your lenses' AF performance comes with time. Yes, certainly it's noticeable. I see it in the results....

When I'm using a fast-focusing lens on a fast focusing camera and I set up both the lens and the camera correctly and am shooting familiar subjects, I get acceptable focus accuracy on upwards of 95% of my shots. When I'm doing something wrong, set something wrong or am shooting with less capable gear, or am trying to capture unfamiliar active subjects, I'll see my in-focus percentages drop.

I always say that autofocus today is far more accurate and much faster than I ever was able to focus manually... and I was actually darned good at it (and had faster reactions, much younger eyes).

I also think that three things affect autofocus performance: the lens, the camera, and the user. The most unpredictable of those factors is the user. Whether focus is right or wrong, it ultimately comes down to me. I know that many... probably most of my focus "misses" are my errors... not any fault of the camera or lens.

imagemeister Loc: mid east Florida

[quote=amfoto1]Some lenses are deliberately designed to focus slower. It is common for macro lenses and portrait lenses with exceptionally large apertures (such as f/1.2) to use "long throw" focus mechanisms. This is done because with at macro magnifications or fairly close distances with large lens apertures depth of field can be very, very shallow... demanding more accurate focus. In these cases the lenses are designed to emphasize focus precision over focus speed. /quote]

Yes, also with this idea in mind, when using tele-extenders, manufacturers deliberately allow the body to sense the extender and the speed of AF is slowed down - either mechanically or electronicly to allow for a greater chance of accuracy - in addition to/of the loss of light to the AF sensors. The magnitude of this extender induced speed loss varies by manufacturer - IMO. I cannot site references for this notion - so do not ask ! It is my experience and knowledge gained over many years.
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