E-M1 CAF compared to D800 question

steppenwolfer wrote:

Currently I own D800 and 80-200 2.8 D AF, mainly as action photography combo (read my dog photography).

Here is my flickr album with some examples: https://www.flickr.com/photos/93055168@N04/sets/72157633815940931

Current combo (d800 and 80-200) also struggle sometimes with my dog - it is smallish and very fast, so it is hard to keep AF point on it all the time. Biggest problem is C-AF when dog comes near me, since in that range lens has longer steps to focus and usually it just can not keep up.

Lately I read that E-M1 with latest firmware is capable of excellent CAF. I also saw good examples from capable photographers. Mostly I see that those results were achieved with 40-150 2.8 lens.

I saw that currently Olympus offer cash back for Olympus 75-300, so I am considering purchase of that lens. How good is this lens for AFC on E-M1?

Is there anyone that used to have D800 and went to E-M1, so can compare C-AF?

I am currently on a kind of a crossroads what should I do. On one hand I have tried and true D800 for which I am considering new 70-200 f4 lens which has very good reputation and weight and size wise is near 40-150 f2.8.

On the other hand, E-M1 + 40-150 2.8 would be my entry to one system photography which in my opinion is better and more friendly to my pocket on the long run. Also my GF is now m4/3 photographer, so she could benefit from this also.

I also considered selling off m4/3 and get bridge camera RX10 or FZ1000 for light travel. But I suspect quality won't be up to standard that I am used to with m4/3.

I would be grateful for any input!

I had the Nikon D800 (and D3s before that) and used it with the 70-200f2.8AF-S and 80-400AF-S. I now have the EM-1 and 40-150f2.8 and Olympus 70-300. I should be in a fairly good position to comment

First thing to note is that the Olympus AF-C speed is on a par with the Nikon D800 and the Olympus AF-S system is much better (no front or back focus and the ability to use pinpoint or magnified focus points). Unfortunately that is not the end of the story and speed is certainly not the only consideration when trying to capture fast, erratically moving subjects.

The Olympus autofocus algorithms are not as good as the Nikon system for quick, erratically moving subjects. With the Nikon system you can use groups of autofocus points so that if the subject moves away from your chosen focus point the immediately surrounding points will hold it in focus. Olympus does not give you this option, so if your subject moves off the chosen autofocus point the camera will lose focus.

(The above ignores the dedicated 3D tracking setting of the Nikon and dedicated AF tracking setting of the Olympus as I have found both of these systems to be unreliable and prone to switch to tracking other objects other than the subject... so I wouldn't recommend using either of the AF tracking systems for action photography).

The above problem is compounded by the other weakness with the Olympus system in that there is a little bit of viewfinder lag (only very, very short - but enough to lose a quick subject which is constantly changing direction). In addition, whilst the high speed frame advance mode of the Olympus uses on sensor PDAF all the time and gives great results for keeping focus on subjects which are predictably moving, there is no live view between frames and so subjects which change direction quickly are very difficult to keep under the chosen autofocus point using that mode. The low speed frame advance mode uses a combination of contrast AF and on sensor PDAF and is slightly less reliable for continuous AF than the pure on sensor PDAF of the high speed frame advance mode, but gives you liveview between frames so that you can at least follow the subject better in the viewfinder.

The D800 has an optical viewfinder and so there is no viewfinder lag as such (only very minor blackout as the mirror lifts). Keeping the subject under the chosen focus point is much easier with the Nikon.

Viewfinder lag of the Olympus can be partly overcome by using the dot sight add-on, but this makes the camera more bulky and becomes less useful for closer subjects.

In short, I've found the Olympus EM-1 is useable for tracking small, erratically moving subjects but is noticeably less reliable than the D800 system primarily due to the lack of group AF modes and viewfinder lag (or lack of liveview between frames). The Olympus will give you a fair number of keepers when you get used to it, but the keeper rate will be noticeably lower than the D800 (and will give you a fair degree of frustration initially if you are used to the optical viewfinder of the D800 which allows you to keep the subject exactly where you want it in the viewfinder).

I'm not in anyway suggesting that the EM1 is not suitable for action photography (it is and I have chosen to use it over my old and much bulkier D800), but if that is your main choice of subject then the D800 is a better bet.

With regard to the Olympus lenses the 40-150 f2.8 is much better at tracking than the 70-300 and seems to acquire and hold focus much better.

Ok. So you are saying in high speed mode (above 6.5fps) EM1 uses PDAF ONLY?
And this is better than combination CDAF/ PDAF in low speed mode (6.5fps and less)?

I knew there was a combination AF going on with EM1 but not that is was PDAF exclusive in high speed.

With legacy glass it is obviously PDAF only regardless.
So with legacy lenses there should not be a difference?
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