Olympus 300mm F/4.0 autofocus performance from wildlife user perspective

I am using Olympus 300mm F/4.0 on E-M1 MK II for more than one year. During this year I had the opportunity to test the autofocus system in different conditions, I tried different settings and found how to maximize the keeper rate. In this article I want to post the best settings I found from my user experience and a lot of pictures with birds in flight.

When I had the first BIF session with E-M1 MK II and 300mm, I got a very low keeper rate - arround 25%. A lot of shots were out of focus.
Then I took shots with static subjects and even in this situation I had some out of focus photos. This was very strange and unacceptable, I thought somethings is really wrong with Olympus C-AF system.

But I did not gave up and I started to check all the settings related to the AF System. Hapilly I found were was the problem. There is a setting - "AF Scanner" which defines how many times the camera will retry to get the subject in focus. By testing the different settings, I found that Mode 3 is the only setting which gives good results. Mode 1 and Mode 2 will limitate the ability of the camera to keep the subject in focus and randomly the focus will fail.
From the moment I set-up Mode 3 on my camera, my keeper rate increased to 60...90% depending of the subject, light...etc.

Here is the list of settings which gave me the best results. Please consider it in this order (most important settings are on the top):

1. AF Scanner to be set-up on Mode 3. The other two modes (Mode 1 and Mode 2) will limitate the ability of the camera to keep the subject in focus not only when the subject is moving, but also when the subject is static.


2. AF Area pointer to be set-up on ON2. This is called also Cluster AF tracking.  It displays the AF target frame in green while the shutter button is pressed halfway. So with the shutter button half pressed you can keep the subject in the frame and see where camera focuses. So you can decide what is to best moment to fire.

3. Try to use less active focus points if is possible. This will increase the focusing speed while it will become more dificult to keep the subject in focus. By example a group of 25 focus points will provide a decent frame coverage and will be good enough for slow birds in flight like herons or buzzards.

4. Focus limiter will also increase the focus speed if the focus range is limited to a lower range. If I set-up my 300mm to focus from 4m to infinite, the focus speed is faster. Focus limiter in the camera will not only help camera to avoid being distracted by the background, but it will also help to see better the subject in the EVF especially when the subject is out of focus. I ussually set-up a range of 4m..75m or 4m..100m.

5. IS disabled. With IS disabled I get slight better results when I shoot birds in flight. I disable it in such situations or use it on AUTO mode.

6. C-AF Sensitivity to be set-up on -2. I got a bit better results with -2 compared to +2.

7. Use C-AF without tracking. The tracking option from E-M1 MK II works OK with slow birds in flight (herons, eagles) but it is not usable for fast birds like swallows or bee-eaters.

8. Firmware 3.0 brought a new option into E-M1 MK II menus - C-AF Center Priority. It sounds good but I did not got positive results at the first tests so I disable it. If I have the chance in the future, I will test it again.
In general, after firmware 3.0 I did not saw any significant improvment for the keeper rate. I get similar results as before.

9. C-AF - Release Priority C - I disabled this option (I set it to OFF). When is enabled, camera could shot even if the AF system did not confirmed the focus. I do not want to get OOF pictures. I prefere a lower frame rate with all pictures in focus.

10. Set EVF refresh rate to high. This will not improve the focus, but will help you to keep the subject in the frame. 

11. Fire short burts and release in between. Releasing the button will increase the ability of the camera to refocus on the subject.


One of the most dificult situations is when there is a distractive background.
Olympus C-AF system does relatively well in such situations, but of course experience&skills makes a big difference here.

In such situation I used 2 strategies:
1. I use a small group of active focus points (ex : 9) and keep this area on the subject. This works fine for slow birds but is very dificult to handle the fast birds like bee-eaters or swallows.
2. I use all focus points activated, then try to keep the bird in the frame and to lock the focus on the target by pressing the shutter button halfway. The keeper rate is lower than in the first case, but it is easier to keep the fast birds in the frame.

At the end, after some practice, I found Olympus system good and I got nice results.

My favourite birds in flight are swifts and swallows because those birds are very fast , dificult to keep in the frame, dificult to keep it in focus. So here it is important to activate all focus points and to have the highest refresh rate for the EVF. To get some focus speed here, I switch the focus limiter from 4m to infinite.
Olympus AF system managed very well.

For fast birds I use:
-exposure time = 1/4000s;
-all focus points activated;
-camera in Manual Mode and ISO=AUTO;
-IS=Off;
-C-AF (no tracking), low fps mode 6...10 fps;
-EVF refresh rate = high.
-F/4.0...F/5.6.

I use the electronic shutter in order to save mechanical shutter's life. Maybe mechanical shutter is slight better, but I could not find any issue with the electronic shutter. So I am using it.

In the past I used for many years Olympus E-5 + 50-200mm SWD + TC.
It was a good combo, I got very nice results with it, was a pleasure to use it.
But 200mm was not long enough in some situations. When I mounted the TC in front, the focus speed was affected, the image quality was affected too.

Now E-M1 MK II + 300mm F/4.0 it's a big step ahead, a perfect combo compared to what I used before:-better C-AF, faster AF, more fps;
-300mm F/4.0 has splendid IQ, I can shoot birds which are 100..200 meters away, then I crop and the picture looks still nice.
-crazy IS;

In my opinion Olympus has a now a very good combo for wildlife, without any things to complain.
I am very happy with it and looking forward in the future to make nice pictures.