Sunday, 17 May 2015

Birds in flight with Canon 7D MkII autofocus

This is an in-depth blog for all you bird-in-flight photographers. Hints and tips on using the Canon 7D MkII autofocus system for photographing birds in flight.


Many of us who used to shoot with the Canon 7D (MkI) have switched to the MkII, but from what I have observed in the hides and on the marshes, many new users are probably not getting the best out of the improved autofocus capabilities of the new camera.

          Figure 1

If I am right, and there are people out there confused by their new camera's options, it is hardly surprising. The CD manual supplied with the Canon 7d MkII is well over 500 pages long. In addition, there is another dense manual dedicated just to the autofocus (AF) system - this can only be found on the web.  You can download the pdf version of this manual by clicking on the download link on this page:

http://learn.usa.canon.com/resources/articles/2014/eos7dmk2_afGuidebook.shtml

I thought it might be helpful to pass on the hints and tips that I have accumulated in using the camera over the last six or seven months. It might help you to decide whether my opinion is worth listening to if you have a look at earlier entries to this blog - all taken by the 7D MkII - or visit my website to see a mixture of photos taken with the MkI and II - please visit 
www.johncrabb.co.uk



There are five aspects to setting up the MkII properly:

1. Set your Autofocus to AI Servo
2. Choose the optimum arrangement of active AF points for birds-in-flight shooting.
3. Set the broad AF characteristics to their optimum values.
4. Set the iTR option to "ON".
5. Micro-adjust the AF settings to suit the lenses you will be using.

and, optionally

6. Set up an alternative selection of active AF points reachable by just a single button click.

All will become clear as we go through each aspect in detail. I am only treating points 1 - 4 in this Blog. I will follow up with the rest if there is any interest - please let me know.

So, here we go!

1. Set your Autofocus to AI Servo mode

You are probably already familiar with this, but just for completeness. Press the DRIVE-AF button (A) then turn the small cogged wheel (B) until "AI Servo" shows up at the lower right of the camera LCD screen.


   Figure 2

2. Choose the optimum arrangement of active AF points for birds-in-flight shooting

The 7D MkII has a total of 65 AF points. Some of these are not available depending on which lens you are using. You can look up these details in the little paper booklet supplied with the camera. Generally though, if your lens + extender combination gives you an effective f number which is equal to or brighter than f5.6, all 65 AF points will be available to you.


    Figure 3

You are very probably already very familiar with how to select your AF points. In brief, you look through the viewfinder and press the button marked with a white square containing five small squares in the shape of a cross (A). This is the very right hand button in the group of three on the back of the camera. When you do this, you will see the selected AF points appear in the viewfinder. You can cycle through the available patterns of points by pressing repeatedly on the M-Fn button on the top of the camera (B). Your options vary from selecting just a single AF point, right through, in ever increasing group sizes, to allowing the camera to auto-select from all 65 AF points. This last one (65 point auto-select) is in my opinion the one to go for. 

Your view through the eyepiece should look something like this, although the centre square point may not be enlarged at this stage. The important features by which to recognise this screen are the curved lines delineating the area, and that all 65 AF points are visible - I am sure that you will know when you have got there!
 

    Figure 4

Why is this configuration the best? Well it is the one that unlocks the full power of the AF system that you have just paid a lot of money for. With the correct ancillary settings, which we will come to in a minute, this option allows the brainy AF system of the 7D MkII to track your bird between AF points as it wobbles about in the viewfinder whilst you strain to keep up with its 30mph passage. Some people, based on their experience with the 7D MkI, select the centre point only. If that is what you choose, then you might as well have saved your money on the MkII because it is not being allowed to do its best for you.

So why is the centre point highlighted in this viewfinder shot from my camera? It is because I have chosen to have this point as the initial AF point. If I can get this on the bird and half press the shutter button to get it in focus, the AF system should then do its stuff keeping the bird in focus as it inevitably shifts about across the field of view - just keep the shutter button half pressed and do not let go unless the bird pops out of focus. If it loses focus just try again.

(There is another possible option here, which is to allow the camera absolute freedom of choice about which AF point it uses to acquire first focus, and this can work well with a bird against an empty sky as there is nothing else for it to lock on to. This is the AUTO option which I discuss below.)

Here is how to set it the way I normally use it (centre spot selected).  Open the Menu and select the option highlighted in the figure below . Press the SET button in the middle of the large wheel on the back of the camera.

    Figure 5

You will then see this:


   Figure 6

Turn the big wheel until the purple highlight is on the first option as shown and press the SET button again.  Now when you half press the shutter button prior to taking your shot you should see the view shown in the Figure 7 below. The centre AF point will appear surrounded by the bracket-shaped lines, the other 64 points will not be visible

   Figure 7

If you do not want the centre AF point to be your initial focus point, just press the white square button (A) that I told you about in Figure 3 and move the selected point about with the tiny joystick button just above and to the right of the Q button on the back of the camera.

The second option that you could have selected in Figure 6 allows the camera to use as its initial focus point the single AF point that you might have been using before changing to the 65 point auto-select option. I don't really see much value in this, but you might!

The third option labelled "AUTO" dispenses with an initial AF point altogether and allows the camera to make its own choice of what to focus on once you half press the shutter button. As I said, this works well with birds against a plain sky. In general, the camera focuses on the nearest object within its field of view if you choose this option. The arrangement I use however also gives the camera a chance of locking on to a bird flying against a background because it is you who selects the object of first focus rather than the camera - and of course you will pick the bird rather than a neighbouring tree!


3. Set the broad AF characteristics to their optimum values.

So, you have now set up your camera to ensure that it has complete freedom to exercise its expensive brain power on your behalf trying to keep the bird in focus. But that is not the end of that particular story. You need to set up the camera so that it is best configured to be able to do that. Go to the first AF menu screen (purple highlight at the left of the five dots at the top of the screen) and have a look at one of the AF cases - you can move between cases by turning the big wheel. I have chosen Case 3, but it doesn't matter which because you are going to change it anyway:


   Figure 8
  
Within each "Case" there are three performance aspects which determine how the camera is going to try to chase the bird around your frame. It does this by switching between AF points to keep the bird under one of them. Getting the right settings tells the camera what to expect and what rules to apply when it is considering changing AF points. There is a long discussion on this in the special Canon 7D MkII autofocus pdf document I gave you the link for.

You can customise each aspect by highlighting the Case you are going to edit, Case 3 is highlighted in the screen shot above, then press the "RATE" button.

Firstly, you will see this. You can scroll down to highlight the other aspects in turn using the big wheel.

   Figure 9

Once you have highlighted the performance aspect you wish to edit, press SET and you will see something like this. Move the white pointer to the chosen value using the big wheel and press SET. Then move to the other two aspects in turn.

    Figure 10

Here are my reasons for choosing the settings that I use.

Tracking Sensitivity - this determines how long the AF system is going to try hold on to a focussed bird whilst other things like branches and reeds might temporarily block the view as you sweep your camera along with it. If you choose a high value, i.e. 2, it will quickly switch to focus on pesky twigs. My choice has been to set it to -2 so that the AF system sticks with the bird even if temporarily lost to view.

You can see the effect in these two pictures of a flying Swan. The first is plain sailing, because it is in the open - no problem.


Then it passes behind some trees, but the Autofocus stays with the Swan and ignores the trees, at least for a while.



Accel./Decel. - As I usually get the bird wobbling about a lot I have set this to value 1. Not quite sure if this makes a lot of difference or if this is the best value. I would be grateful for feedback on this.

AF point auto switching - This is obviously very important as it determines the readiness with which the camera will move to another AF point if it detects a change in the bird's position. You want to do this as soon as possible, so select numeric value 2.


4. Set the iTR option to "ON"

iTR AF stands for Intelligent Tracking and Recognition Auto Focus. This is the magical feature that tells the AF system to remember the shape and colour of the object which it first locks on to. Obviously with this extra information it can much better track the object which you are actually interested in - i.e. the bird.


    Figure 11

Select the item highlighted in purple. Press SET to see your options, and move the selector with the big wheel until ENABLE is highlighted, then press SET. This screen is not shown, but it is very obvious.


Note, that the iTR feature only works when multiple AF points are available to choose from, just as I have described above. It does not work with just the centre point selected as there are no other active points for the system to switch to!

OK, now you are good to go! Happy shooting!

NB The second part of this article on Autofocus adjustment is now available and may be found at:

http://johncrabbwildlifeimages.blogspot.co.uk/2015/06/fine-tuning-7d-and-7d-mk2-autofocus.html


You will also probably be interested in this blog on the use of Lens Extenders or Teleconverters http://johncrabbwildlifeimages.blogspot.co.uk/2015/07/do-lens-extenders-ruin-image-quality.html

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My Website showing a selection of my photographs can be found at:  www.johncrabb.co.uk        

You can also "like" my page on Facebook and keep up with all the latest goings on at:
www.facebook.com/johncrabbwildlifeimages


You may also like to read my Blog article on the effect of Lens Extenders, or Teleconverters, on the quality of wildlife images.
 http://johncrabbwildlifeimages.blogspot.co.uk/2015/07/do-lens-extenders-ruin-image-quality.html

It has some perhaps surprising conclusions!
 
Meanwhile, here are a few shots to view just before you go. Thanks for visiting and please do share this blog with your friends.