CAF Focus problems with the EM-1 - a possible answer

[brian1208]

I have been reading various threads here and elsewhere about the problems some people are experiencing when trying to use CAF to shoot moving objects, BIF in particular

After a fairly lengthy on-line "chat" with one person who was reporting that they were getting fast initial focus lock but when trying to maintain this when tracking the bird the focus just "wandered off all over the place".

It turned out that this was specifically related to his use of C-AF + tracking and that when he reverted to using CAF the problem disappeared.

It reminded me that some time back I saw a post from Ian noting that the "Tracking" function on the EM-1 was not designed to meet this function and that it should not be used when shooting BIF or other action subjects

This has certainly been my experience and is very different from my experiences using the predictive tracking function of the canon 7D.

It got me wondering how many of the people who are reporting CAF tracking problems were doing so because they hadn't appreciated this fact and were in fact trying to use C-AF + tracking to shoot BIF instead of C-AF without tracking?

[DerekW]

Re: CAF Focus problems with the EM-1 - a possible answer

So where would one use the "tracking" option?

[benvendetta]

Re: CAF Focus problems with the EM-1 - a possible answer

To me, this is the sort of situation where you would need tracking as the green box should lock into the suject ans maintain focus.

[StephenL]

Re: CAF Focus problems with the EM-1 - a possible answer

So where would one use the "tracking" option?

On a relatively static subject where you wanted to maintain focus whilst recomposing. That re-composition might in this scenario include fore and aft movement as well as lateral. Think of it as a sort of dynamic focus lock. I suspect the word "tracking" is somewhat misleading.

[TonyR]

Re: CAF Focus problems with the EM-1 - a possible answer

I have not tried the tracking option. All my issues have been with C-AF.

[brian1208]

Re: CAF Focus problems with the EM-1 - a possible answer

If I remember Ian's input correctly it is for those situations where you need to get focus lock on an individual in a group then maintain focus on them as either they move through the group or you recompose.

Hopefully he will spot this and come in with the definitive answer

As so frequently seems to be the case, the manual is less than helpful:

C-AF:

The camera repeats focusing while the shutter button remains

pressed halfway. When the subject is in focus, the AF con

formationmark lights up on the monitor and the beep sounds when the focus

is locked at the

first and second time.

Even if the subject moves or you change the composition of the

picture, the camera continues trying to focus.

and

C-AF + TR:

Press the shutter button halfway to focus; the camera then tracks

and maintains focus on the current subject while the shutter button

is held in this position.

• The AF target is displayed in red if the camera can no longer track

the subject. Release the shutter button and then frame the subject

again and press the shutter button halfway.

• With a Four Thirds system lens, the tracking range narrows. If

the AF target is displayed in red, AF does not operate even if the

subject is tracked.

Stephen , you beat me to it, thanks for confirming my memory

[photo_owl]

Re: CAF Focus problems with the EM-1 - a possible answer

I have only had reason to use C-AF+T a few times but it seemed to work as expected.

27 frame sequence of a surfer, where he leaves the selected AF point quite a few times is an example of where it seemed the right mode to use.

Surely the main issue with BIF is that they will be constantly changing their 'form' and as such the tracking alogrithm isn't going to easily recognise them as the same target you started on? C-AF maintaining the AF point on the target will resolve this. On the E3/30/5 the diamond AF points worked together to maintain a lock on the initially selected target and, on top of that, PDAF has a concept of focus distance to lock such that they could use predictive alogrithms to support maintaining the subject in focus as it moved both across and in and out (as do the Canikons with good PDAF - many with better in this area).

I'm looking forward to some motorsport opportunities to test more thoroughly - I would just go out on the roads but people seem to be overly concerned when they see someone pointing a camera at them!

[benvendetta]

Re: CAF Focus problems with the EM-1 - a possible answer

What mode would you use for track cycle racing? I am going to Newport Velodrome to get some action shots on Saturday. Riders will either be coming straight towards me for the finish line, and at an angle from the banking.

[Ross the fiddler]

Re: CAF Focus problems with the EM-1 - a possible answer

A wedding would be a good use for C-AF+Tr & I would imagine (haven't tried it) the E-M5 could track the bride in most cases, photographing her as she moves down or up the aisle & the E-M1 should be even better.

[gazza95]

Re: CAF Focus problems with the EM-1 - a possible answer

Brian,
have tried tracking and face detection at various points and quickly switched both off. While these may work with CDAF it just seemed to confuse things with PDAF.

Maybe my understanding of tracking is wrong. I was expecting to use single point to select target and then camera to move target point with subject. This never seemed to happen so I stopped using it.

I had hoped face detection would help when photographing rowers. Unfortunately it never really identified the faces even when zoomed in.

Gary

[birdboy]

Re: CAF Focus problems with the EM-1 - a possible answer

When I first had the EM1 I was under the miss understanding that tracking function meant following something moving. It was only after Ian's postings that I had a better understanding of what the Olympus designed had meant by tracking. Since then I only use tracking for pictures of my grandson as he seems to have difficulty keeping still.

I am in the fortunate position to have both the E5 and EM1 and I have to say that CAF on the EM1 does not do the job for me as of yet. At the moment I have gone back to using the E5 to see if my recollection about the performance of the E5 is real. I have to say that I feel it is. While I am not getting pin sharp bif I am at least getting them in the frame consistently.

I should say that I am using FT lenses for bif and nature. I think the EM1 will perform really well when Oly come out with a fast telephoto lens in mFT.

I am wondering if the problem lies in the number of AF points and the processing power. There is something different about the way the EM1 chooses the point on which to focus compared to the E5 and at the moment I do not understand what it is doing.

[brian1208]

Re: CAF Focus problems with the EM-1 - a possible answer

Surely the main issue with BIF is that they will be constantly changing their 'form' and as such the tracking alogrithm isn't going to easily recognise them as the same target you started on? C-AF maintaining the AF point on the target will resolve this

That is certainly my experience and so long as I keep the focus point where it needs to be I find no problem with BIF shooting, (but others are reporting a different experience which is why I put this thread up)

Gary, my findings were much the same, I never use face detection nor tracking for my type of work as I haven't been able to get them to perform as I'd hoped and have given up trying.

There is something different about the way the EM1 chooses the point on which to focus compared to the E5 and at the moment I do not understand what it is doing.

that is the impression I get to only in my case I have no experience of 4/3rds system cameras and lenses so my comparison is back to canon. This is why I basically had to forget everything I knew about setting up my canon bodies and start from new with the EM series bodies + m4/3rds lenses (trying to do it "the canon way" drove me round the bend as it never worked how I expected)

Dave, in your situation I use SAF + 6 or 10fps, I would essentially pre-focus on the point they come into view, lock and fire a sequence, or shoot a short burst, then refocus as they get closer to the finish line (I found SAF was fast enough doing this to acquire racing m'cycles coming straight toward me at similar, relatively close, range)

[dogsbody]

Re: CAF Focus problems with the EM-1 - a possible answer

Elsewhere on this forum I have mentioned my confusion over what I consider to be disappointing results with BIF. So prior to reading this thread I contacted olympus service for their advice, the chap was very helpful but.....
I was I advised to use AF + Tracking

[brian1208]

Re: CAF Focus problems with the EM-1 - a possible answer

Interesting, try it and see if you can get it to work for those of us who can't

(I don't pretend to know enough about the Olympus system to make sensible comment but can only flag up what I saw Ian and others say and relate that to my own experience )

[dogsbody]

Re: CAF Focus problems with the EM-1 - a possible answer

Interesting, try it and see if you can get it to work for those of us who can't

(I don't pretend to know enough about the Olympus system to make sensible comment but can only flag up what I saw Ian and others say and relate that to my own experience )

Brian I hope that you took my post in the manner in which it was intended, I was trying to express my confusion not to allude that one piece of advice was right and t'other wrong!

In my short enjoyable time with the camera - (and that includes time on this forum) I am beginning to think that the EM-1 is a camera that needs to be set to the individual user in order to get the best out of it. I think it is far from a point and shoot tool; which I think is a good thing. Clearly some on this forum have reached that point and are getting superb results! Whereas some of us (me) are still trying to get the best out of the camera. I used to indulge in a sport in which I found there were so many different ways to get a good result, It took me some time to do so but I did in the end! and I see parallels with BIF

Now looking at the images on the back of the display I think they do look a bit sharper* Which could be due to the following....

a) I increased the number of active focus points,
b) benefitted from nice light
c) The seagulls were closer
d) The use of AF + Tracking
e) The fact that I am aware that I hestitate in pressing the shutter release and so I am trying to speed up my action. (I blame clay shooting- it is a long story)

* may not be on a bigger monitor though

either way it is fun trying, if it was easy would the 'great shot' moment be as satisfying?

regards,

Jonathan