Configuring your 5D Mark III AF for fast action
March 12, 2014
The Canon EOS 5D Mark III has a very sophisticated AF System, with a vast number of options to setup its AF behavior, which is capable of some really stunning results. The possible combinations to tweak the AF properties are basically unlimited, so especially for beginners it can be hard to assess which configuration will yield the best results. In this article I'd like to give some insight on how to setup the 5D Mark III AF-system for the most challenging of situations – small, fast moving objects who change speed and directions quickly – such as birds in flight. Of course the techniques described here will help you with all kinds of action photography but BIF is in my opinion one of the most demanding photographic situations when it comes to AF, so I will concentrate mostly on that.
The 1DX and 5D Mark III basically have the same AF-system so this article should be equally valid for both cameras. However I never used a 1DX so it is possible that this camera will react a bit different than I'm describing in this article.
A short remark on the pictures in this article: All images were created by me using a 5D Mark III, a 500mm f4 L IS II USM lens (hand held) and the techniques described below. When AF points are shown which could have been used for focusing, please know that those are not necessarily the ones that were actually used – those pictures are for instructional purpose only. It is also possible (likely in fact) that the images shown here are cropped and the positions of the focus sensors were in fact very different when the image was shot.
To reach maximum AF performance with the 5D Mark III some requirements have to be met. First and foremost a sufficient level of light has to be present, the air should be clear and free of heat haze (those are especially problems at air shows) and your subject should have a good distance to the background.
Naturally the lens you use plays a major part since it is the component that is actually focusing. I wouldn't recommend any lens that is not equipped with some kind of ultrasonic motor since only the fastest focusing lenses are up to the task. All shots on this page were made using a Canon EF 500mm f/4 L IS II USM which falls into the lens group C. Group C means all the cross-type points are usable (although not the double cross type functionality for f/2.8 lenses) and this group or higher will be perfectly adequate for even the most challenging of conditions.
If your lens has an AF range selector USE IT! Your subjects will typically be further away than just a couple of meters and focus acquisition and focus hunting should be vastly improved if the camera doesn't try to look for focus up close. If you are so lucky to be able to use one of Canons super telephoto lenses you can further improve focus acquisition speed by using the focus preset feature but I will show how to do that further in this article.
Finding and following your subject
There are some subjects who can already make the task of getting and keeping them inside the frame of a long lens a major challenge. From personal experience I think of falcons and hawks in this regard. I will describe some techniques for the advanced user which should help you on this task further down in this article.
General AF setup
The 5D Mark III has a couple of different presets for AI Servo which are accessible via the first page on the AF tab in the menu. My recommended setting for most of my fast action needs is shown in the picture below. Basically it doesn't matter which preset you choose since none of them is suited for really demanding BIF work in my opinion, and the true setting is anyways defined by the parameters of the bars on the bottom right of the screen.
I have found these settings to be fitting most birding needs very well, but since situations aren't always the same it will be advantageous to modify these setting when required. So please see my recommendations as a good starting point and not as the ne plus ultra.
Let me quickly explain why I adjust them this way:
As you can see in the picture I use the 'tennis player setting' as a basis for my AF configuration. The reason for this is described by the camera manual quite well: 'The camera will try to continue focusing the subject even if an obstacle enters the AF points or if the subject strays from the AF points. Effective when there may be an obstacle blocking the subject or when you do not want to focus the background.' (5D Mark III manual)
It is a very important property of the cameras behavior to try to keep the focus always on the subject. For example when your subject passes behind a tree the camera must not get distracted and focus on the tree or if you briefly lose the subject out of the frame (which will happen quite frequently) the camera must not focus on the background. I recommend using a tracking value of -1 which works quite well for me in most situations. A value of -2 would most likely get the job done either but a disadvantage can be that if you accidentally focus on the background it can get quite hard and take some time to get the focus back on your subject - time that will probably make you miss a couple of potentially great shots.
Since birds can change directions quickly their relative speed towards/from your camera changes quickly as well, even if they don't accelerate/decelerate from their point of view. I recommend configuring the camera to a accel./decel. tracking value of +2 which means that the camera will not hesitate on giving an immediate response on every measured mis-focus, a behavior that could be considered as being a bit 'nervous' but is in my opinion inevitable for fast and inconsistent moving subjects.
AF pt auto switching
When it comes to fast action photography it is in most cases already quite challenging to keep the subject inside the frame, keeping it under a certain AF point is nearly impossible. For this reason it is in most situations necessary to let the camera decide which AF point to use. Setting the value for AF pt auto switching to +1 will ensure that the AF follows the movement of the subject inside the frame, and proved to be sufficiently fast for my needs.
Lens drive when AF impossible
This is a rather specialized setting on page four of the AF tab which is normally turned ON. If you change this setting to OFF it means that if the AF sensor can't initially detect where it has to focus it immediately stops to look for focus without searching through the whole range.
This is very important when using a super telephoto lens since due to the very thin depth of field the lens can get vastly out of focus when it searches in the wrong direction. Additionally you may not want to use the focus range limiter on a super telephoto lens because the new minimum focus distance of the 'long range' is probably quite far away (10m with the 500L II, 16m with the 600L II).
On every other lens you should be perfectly fine when this setting stays ON and you just use the focus range limiter.
Specialized AF settings
OK, now that we have covered the general setup let's take a look at some specific situations.
The 'easy' ones
Let's take it slow. Not real slow but comparatively slow. Bigger birds cannot accelerate or maneuver as quickly than smaller birds and are therefore easier to shoot. Birds such as eagles, vultures, herons, pelicans, geese and ducks (not for their size but for their tendency to fly straight and predictably) fall in this category. Photographing these is way easier than the really fast species and as a beginner one should start here. Most demanding action photography other than BIF would also fall into or even below this classification (think of field sports, motor sports, horse racing etc.). I will refer to this category from now on as 'slow action' although it is not literally slow.
AF area setup
In every photographic situation it is optimal when you can control the AF area as precisely as possible. For example if I shoot portraits I use Single-point Spot AF on the eye of my subject which is closer to me and achieve perfect focus exactly where I want it. Unfortunately in action photography it is not possible to move the AF point around so quickly (and recomposing is also not an option for obvious reasons) so it will be necessary to utilize some form of AF area selection.
My preferred choice for slow action is Zone AF. Zone AF gives you the ability to select the part of the frame where you would like to achieve focus. If a bird flies from left to right you can use a framing like in the image below with an appropriate amount of free space in front of your subject. This makes for a pleasing composition in this case but the question is what will you do when your subject changes direction and you will have to focus on the other side of the frame quickly? Well, this is where back button AF comes to play.
Before I continue any further I'd like to briefly describe what back button AF does:
Some photographers like to control AF and light metering independently, so they configure their camera not to focus when the shutter button is operated. Instead they use the AF-ON button on the back of the camera for AF. I strongly oppose this method because you lose a major advantage the 5D Mark III offers: focusing on two different focus points or areas with two different buttons. My usual setup incorporates the AF-ON button focusing on the left side of the frame while the shutter button focuses on the right side (this seems logical to me since the AF-ON button is physically more to the left and the shutter button more to the right).
A step by step instruction on how to setup back button AF to focus on a different zone than the shutter button:
- go to the Custom Controls menu (custom functions tab - page 2)
- select AF-ON
- select AF and metering
- press the INFO button
- select HP (home point)
- leave the menu
- set the AF area selection mode to Single-point AF
- select one of the leftmost AF points
- Hold down the AF point selection button (top right of the back of your camera) and press the LCD illumination button (the light bulb)
- This point is now registered - if you move the AF point somewhere else it will blink. You can find more details on registering a home point in the 5D Mark III manual (for firmware version 1.2.0 or later) on page 330.
- set the AF area selection mode to Zone AF
- select a zone on the right side of the frame (the previously selected home-point will still blink)
You're done – test if the shutter button focuses the right side and the AF-ON button the left side of the frame.
If you do not register a home point the camera will focus on the center zone when pressing the AF-ON button which can be -depending on your situation- equally fine or even preferable. You can delete your home-point selection by holding down the AF point selection button and then pressing the ISO button.
Learn to use this configuration – internalize to focus the right side with your index finger and the left side with your thumb until it becomes second nature. This is the fastest method of AF zone selection I can think of and that is what you need when shooting action. Of course I'd like to encourage you to setup your zones differently depending on the conditions (top/bottom etc.), what counts is to be able to utilize more than one zone at a time.
On a side note: Incorporating two AF points simultaneously is a technique that also serves me well when shooting candid shots of people in One-Shot AF mode.
Congratulations! When you have read and followed this far your AF setup for the majority of action situations is complete!
Now the really hard ones
After quite a significant amount of practice you will probably want to face the real challenge – really fast action photography (referred to as 'fast action' from now on). I would characterize this category as follows:
- The subject moves not only fast but also very unpredictable.
- The subject is quite small and a very long lens is needed to adequately fill the frame.
- It is quite impossible to keep the subject inside the frame for more than a couple of seconds.
- It is absolutely impossible to choose where on the subject to focus.
- Composition is often achieved by luck and in post-production via cropping.
AF area setup
When we have to deal with a situation where even framing the subject is a challenge on its own, limiting the AF area on a zone will usually fail. The only viable AF mode in my opinion is 61-point automatic selection AF. After initially achieving focus on the selected AF point the camera will use all AF points automatically to follow and focus the subject. This means you have to ensure that you choose the best possible basic setup, but when it comes to the action you need to put your trust into the camera.
When shooting in situations with a good background separation (difference of subject to background via brightness, contrast and partly color) the results will usually be more than satisfactory, a weak background separation makes the 5D Mark III often stray from the subject and focus on the background (The 1DX should manage noticeably better in this regard).
This technique is also often suited when shooting slower action, and sometimes it is quite hard to decide whether Zone AF or 61-point automatic selection AF is better for a given situation. When your camera takes over the task of selecting focus point you have much more freedom (and time) in creating a pleasing composition, the downside of course is that you can't specifically focus on a desired part of your subject (usually the head).
Luckily a possibility to combine Zone AF and 61-point automatic selection AF exists via back button AF, which I pretty much discovered like some monk once discovered champagne – by accident. This is not described in any manual and I have never read about it anywhere on the web, so it's likely you are not aware of this function.
- switch to AI Servo AF
- select 61-point automatic selection AF (you should now see the whole AF area outlined and one single AF point for initial focus achievement)
- select the AF point in the center of the frame (this is not strictly necessary but practical)
- save this point as your home-point via holding down the AF point selection button and pressing the LCD illumination button like already explained before
- switch to Zone AF
Now something weird but very awesome happens. As long as you use the shutter button the camera uses Zone AF for focusing on the selected Zone as you would expect, but when you press the AF-ON button the camera will immediately focus with 61-point automatic selection AF by initially acquiring focus on the previously saved home-point. This setup gives you the option to quickly move between Zone AF and 61-point automatic selection AF so that you can adapt your AF system behavior to rapidly changing conditions. I have actually no idea why such a useful function is not described in the camera manual.
Some words on continuous drive mode
During the exposure the camera will not be able to continue focusing on the subject so a high frame rate is somewhat contra productive for achieving perfectly focused photos. I normally avoid using continuous shooting ('spray and pray') and time my shots to capture the decisive moment. This however strongly depends on the situation. If your subject doesn't significantly change distance to the camera (e.g. the fishing seagull image in this post) continuous shooting is perfectly adequate, if you try to shoot birds that are flying towards the camera on the other hand, continuous shooting will decrease your keeper rate significantly. In my experience the keeper rate drops so much that you end up with far less usable images when continuously shooting rather than using well placed single shots, so I rarely press the shutter more often than 2-3 times per second. You can see through the viewfinder if your subject is momentarily in focus or not – time your exposure accordingly.
Additional hints for using super telephoto lenses
Contrary to some people's beliefs, using a super telephoto lens doesn't make birding easier. In fact, I believe using superteles is harder for the following reasons:
- Super telephoto lenses are heavier so you will either want to use some kind of support which will restrict you or you use them hand held which will tire you.
- Their field of view is very narrow so finding and following your subject becomes a real challenge.
- When using the focusing distance range limiter the close focus distance will be quite far away so this is not always an option.
- Depth of field is very thin which makes achieving critical focus much more crucial.
If you however manage to take well framed and focused images the results that you get from a supertele lens will be far superior to any other lens, so in this chapter I'd like to provide some tips which will help you overcome the aforementioned restrictions.
Concerning weight there is really not much you can do. My 500L II is so 'light' that I'm able to use it hand held even for longer periods of time, which doesn't mean that it is comfortable to do so. A 300 f2.8L II with extenders would be even better in this regard. I do not even own a tripod/monopod so I can't comment on supported shooting.
Finding your subject
You can probably imagine that finding a small, fast moving subject in the sky with a lens that has a 5° diagonal angle of view is not exactly an easy task. If you're using a zoom lens you're lucky – just find your subject at the wide end and then zoom in. For fixed lenses I developed the following technique:
- Use your right eye to look through the viewfinder and use your left eye to observe the scene.
Your brain will now want to eliminate the 'wide angle' view of your left eye and only concentrate on the tele view through the lens. Learn to suppress this behavior – practice concentrating on either eye at will and learn to blend both images together so that you can see both scenes simultaneously. (This will of course take some time to master!)
- Realign the camera so the AF point that you see with your right eye moves onto the small subject that you see with your left eye. The magnified subject will appear in the frame.
Please realize that this technique really needs some practice to master but after some time you'll be able to get any moving object inside your frame quickly. I would also like to point out that what I'm describing here is really for advanced users – don't try to learn everything I write in this article at once – you know Rome wasn't built in a day either.
Using the focus preset feature for faster AF acquisition
As already described earlier it is probably not always desired to limit the possible focus distance range to the distant section. Even if your subject is normally further away it will be very frustrating to not being able to focus if it by chance gets in close, and to miss a potentially great shot. This is how I deal with this problem:
- Set 'Lens drive when AF impossible' to OFF.
- Set the focus distance range limiter to full range.
- Manually focus to the last numerically indicated distance on your distance scale (30m in the case of the 500L II).
- Save this distance via the focus preset feature.
Due to the 'Lens drive when AF impossible' setting in OFF position your camera will not attempt to focus closely and will only stay in the outer focus distance range where your subjects usually are. If your subject gets in close the focus will follow even into the close range because you're focusing on it continuously. If you want to return to the far distance simply turn the playback ring on the lens. From this position you'll be again able to quickly acquire focus on your distant subjects.
In retrospect this article got quite a bit longer than I initially anticipated. Do not let yourself get overwhelmed by the amount of information - it is absolutely not necessary for you to learn and use everything that is described here. My wish when I created this article was to offer you some help when dealing with the really challenging action situations. Pick the procedures and methods that you like and incorporate them into your shooting style.
Bear in mind that what is important is not to memorize the camera settings I use, but to understand how changing settings will affect the cameras behavior. Always try to observe what your camera does wrong and think about how to adapt your setup to better deal with a certain situation. Experiment and practice! Don't try to imitate someone else - develop your own style!
To conclude I'd like to sum up my experience from using the 5D Mark III for action photography:
- If you are quick enough to get a subject into your frame the 5D Mark III will be quick enough to focus it.
- If focus doesn't turn out well the fault is not with the camera. You didn't tell your camera on what or how to focus exactly enough (via the settings) and/or didn't apply the right technique.
- Reacting to situations is very important – learn to change settings without taking your eye from the viewfinder and use multiple AF Zones at once.
- Your AF point/zone selection should be as precise as possible but not too restrictive.
- High quality L-lens/teleconverter combinations that fall at least into lens group C will be perfect, but combinations up to group E (with a resulting maximum aperture of f5.6) should still be sufficient for even the most challenging situations.
- If you are wondering if you should upgrade to a 1DX only because of better AF performance – no, you shouldn't. Without a doubt the AF performance of the 1DX is better than the 5D Mark III (better tracking capability, faster lens drive due to higher battery voltage, dedicated AF processor, …), but I have found the 5D Mark III being good enough for anything.
- Your skill is the bottleneck of getting perfectly focused images, not the 5D Mark III AF system.