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E-M5 Auto Focus Options Part 2
Like most advanced cameras the OM-D (E-M5) offer the user several ways to adapt the camera Auto Focus (AF), and to fit it to his or hers own style. Multiple processors, improved AF algorithms and a completely new Image Stabilization (IBIS) assembly are only parts of the new technologies pushing the E-M5 into a reference position. In this short article I like us to discuss the different S-AF configurations. I will also add a few more ideas not necessary linked at configuring the E-M5 Auto Focus but things that could help you tune your E-M5 to better fit your own behavior and style. Lets have a quick look at the E-M5 Single Auto Focus behavior when the camera is in full "Auto" Mode.
While in full Auto Mode the E-M5 will automatically apply a number of advanced S-AF (Single Auto Focus) options while finding the best "in-focus plan” for the scene in front of the camera. These options could include a single Auto Focus Frame measurement or in the case of a landscape scene the camera could decide to focus on multiple AF Frames in the scene. Lifting the camera the first thing you will notice is the camera will do a quick scene recognition and like in the above image it could recognize the person in the scene. Recognizing the person, the camera will place the persons face inside a white market box even before the shutter is pressed. When pressing the shutter halfway, the camera will position the green AF Frame on the person.
The above steps determine how the camera will adjust the scene exposure while focussing on the person's face. In fact the E-M5 will automatically focus on the person's eye, the preferred focus point when working with portraits. The camera will also do a full scene exposure measurement plus it will optimize the exposure and white balance (skin tones) on the person. All this happens in a split second and without much thought or effort from the photographer. If fitted and flipped up, the camera could automatically trigger the flash when recording the image. Finally when pressing the shutter all the way, the camera will also automatically stabilize the camera sensor while taking the picture. In this short example you can see just how many things happen when taking the image, often without the photographer even realizing.
Sometimes I believe camera manufacturers build more intelligence into the camera Image Stabilization systems as what we expect them too, especially those using in-camera Image Stabilization like the E-M5. Reason I say that, is I found with almost every Olympus camera I owned, that the image sharpness improves the longer I use the camera. I agree and the obvious part of the puzzle is me (user) getting use to the camera and not so much vice versa. Question is, will I also get use to the IS cycles inside the camera or could it be that the camera tunes itself to my "shake profile" by getting used to my unique movements when taking an image?
Before I continue let me list a few important AF configurations you see in the article:
Single AF Frame - the normal green auto focus box on the camera screen
AF Zoom Frame - Special AF box that the user can zoom into - see article
Group Target AF Frame - 9 AF frames in a 3x3 format on the screen - P44
At first I planned to discuss each of the below listed settings or remarks in more detail. But thinking more about that I realized the article can become really heavy and possibly not so interesting. I therefor decided to rather make a list of all the key settings or configurations on the E-M5 plus other factors that could influence the effectiveness of the in-camera S-AF system. Lets therefor have a look at the short summary AF settings on the camera plus any additional points that will better stabilize and support auto focus when using your E-M5:-
Adding the HLD-6 grip part and not necessary the extra battery holder
Place the camera against your eyebrow when looking through the EVF
Set High Speed fps IS to OFF - E-M5 always IS also at 9 fps - P87 / 56
Holding the camera correctly:- Camera holding techniques
Program 1/8 th shutter delay (anti shock), slows down the AF cycle - P89
Cancel the histogram during the live view & Image recording cycle
Select, "Half Way Rls With IS" - IS starts when the shutter is halfway - P87
Instead of Single AF Frame, Use Group Target AF Frame configuration - P44
Set "RLS Priority S", to Off - Shutter will only release when focus OK signal
The "Auto Focus OK", Green Dot different indications, find, learn & use
Set "Full Time AF" to ON, the E-M5 continuously AF when E-M5 switched on
Learn how to use the AF Zoom Frame function for accurate focus - P45
Up the Auto ISO upper limit to 3200 - this ensure higher shutter speeds
Look for vertical lines in the scene P98 in users manual (Shade or darker areas)
Calibrate your E-M5 levels, will ensure camera "see" verticals correctly
Dial-in lens focal length when using zoom lenses - P49
Never under estimate the value a stable support, tripod, bean bag....
In critical situations a tripod plus shutter release cable a must
When using a support like a tripod de-activate IS
Its critical to learn where in the scene you should focus for best results
See P44 for more on Focus Lock information.
You can decide to use any of the above steps or to combine those points which you find work best for you. I lost my left arm in a motorcar accident and therefor shoot with one hand only. In my personal case I found the following to really work well for me, those of you shooting compacts with one hand might find some ideas in the list:-
I added the HLD-6 grip part to my E-M5 for better stability
I use the Group Target AF frame for casual shooting
For accurate work I will switch over to the AF Zoom Frame
I assigned the AF Zoom Frame function to a button on my E-M5
I use the "Full Time AF" to ON - This has a calming effect on my style
"RLS Priority S", set to Off - Camera will take the image when in focus
"Half Way Rls With IS" - activate IS when pressing the shutter halfway.
I do not use the histogram in live view, I only use it in image review mode
I set the Auto ISO upper limit to 3200 - In critical cases I set ISO manually
I calibrated the levels on my E-M5 - simple procedure in users manual P
In high speed fps I set my E-M5 to 8FPS plus IS to always ON - P87 / 56
Check that the lens focal length is correctly set in stabilizer (IS)
More information to my above AF Plan
The HLD-6 grip helps me to better hold the camera plus to press the shutter button with more control. The add-on grip does make the camera a little bigger and that you should keep in mind. On the other hand it is really easy to fit and remove the grip.
Why do I prefer to select the Group Target AF Frame option? I will basically use two options when doing Single Auto Focus (S-AF) with my E-M5. The first being the Group Target AF option and the second the AF Zoom Frame option. When casually shooting with my E-M5 I prefer using the group target AF Frame option. When I need to focus accurately on a spot in the image then I will switch to the AF Zoom Frame option. I assigned one of the E-M5 buttons to the AF Zoom Frame option.
Based on the comments Timur made on DPReview plus adding to it my own experience with the E-M5, I feel comfortable that the following description capture how the E-M5 determine and hold AF on the subject. While the shutter is pressed halfway, the camera will look for more references on the same “subject” focus distance or pane, indicated by the RED line with arrow heads in the illustration below. The E-M5 will identify those “same distance” targets as alternatives should it loose its focus on the subject. In the image below these “same distance” targets could be points Y and Z and the AF subject being point X. This will prevent the E-M5, AF system from hunting between possible back and front AF points in the scene plus it makes that first focus contact extremely fast, knowing that it has a backup AF if needed. In my own mind the Group Target AF frame will support this theory. It is as if you say to the camera it’s OK to find and use a back up reference when using the target AF group configuration. If only the E-M5 users manual gave more complete information..... All said, keep in mind that the AF Zoom Frame function uses another technique to focus on the target, especially when fully zoomed into the AF Zoom Group Target AF frame.
I know from my E-P2 and E-PL2 days that the histogram will add an additional load to the camera CPU. In addition the histogram on the E-M5 is not as good and informative as the one on the E-P2 and I therefore decided not to use it during the image recording cycle. If you really want live feedback during the recording phase then using the highlight / shadow function.
Full Time AF set to ON is a great help and really effective in my own case. The AF system is always switched on and enables the the E-M5 to always keep the scene in front of the camera in focus, also when the shutter is not pressed halfway. By using this function you will also develop a good feel for what AF points the E-M5 typically select. I also like to activate the "Half Way Rls With IS" function. This function activates IBIS when the shutter is pressed halfway. It feels like a lens with build in IS plus it adds tremendous stability to the final focussing stage. Highly recommended. The E-M5 is really great on high ISO settings and I found it no problem upping the upper auto ISO limit to 3200. This will generally increase shutter speeds at constant aperture values and therefor further reduce the risk of camera shake. Do not hesitate to use the SCP (Super Control Panel) to set a fixed ISO value when shooting critical images. In fact on a clear day I go away from auto ISO and almost always select ISO 200.
Personally I do not use the following technique but have it on the main list. The 1/8 th shutter delay (anti shock) is an option to generally better stabilize the E-M5 in the user’s hand when taking the image? The E-M5 has an Anti Shock function build-in that will add a small delay between the moment the shutter is opened and the sensor reading the image. This is a common function on high end cameras and when using cameras fixed to a tripod. The shutter mechanism has energy stored in the shutter mechanism when operating the shutter. This energy release into the camera in the form of camera shake when taking the image. The 1/8 th second delay helps you to prevent the sensor from being effected by the small shutter vibration PLUS it generally slows down the E-M5 just a little. In many cases this helps the user to be more accurate plus stable. It feels strange when using this technique the first time, its important to take the time to get use to this unique technique. In normal circumstances this function works wonders when doing night or blue sky photography using a tripod. See P89 and P56 for more info
Finally I like you to have a look at one of the previous articles I wrote on using the AF Zoom Frame function. Figure B illustrates how to adjust the AF Zoom Frame using the touch screen. Figure A shows the standard 35 times AF frames layout on the E-M5. I found that the challenge E-M5 users has is to find an accurate focus target which the camera will focus on, especially when using the standard sized, AF Frame on the E-M5. Have you noticed how BIG that AF frame really is and how many things fit into the AF frame? You can easily fit two subjects at different distances to the camera into the AF frame, on which will the camera focus? The only and best solution today is to use the AF Zoom Frame function and then to use the 14x magnified AF Zoom Frame. You can do the AF Frame size, calculation yourself. If the screen or view consist of 35 AF Frames as in Figure A, how large are the physical size or area the camera will scan, using the default size AF frame? I think most of us will get a fright when we see just how general the AF frame really scan when using the standard or default size AF Frame.
The next question is how does the camera use the AF Frame to focus onto the subject, does it focus inside the AF Frame, on the edges of the frame or a combination of both? Again if you feel like finding the answer, I think this will be an interesting experiment to discover exactly how the AF Frame is used by the camera. These questions plus my own experience with the E-M5 made me decide to work with the Group Target AF Frame when casually using the E-M5 in the future. Will I personally use the full 35 frame selection in AF mode? My logic tells me that the camera only really need the full 35 frames when in continues AF (C-AF) or when in tracking mode (C-AF + TR).
I wrote a basic camera configuration article talking about the basic settings and adjustments when setting up your E-M5. I regularly update this article to include my experiences plus new settings on my E-M5. Reading that article will help you better understand how I implemented the above discussed Auto Focus settings and ideas. Always see the date on the article to ensure you get the latest or updated info.
One of the posters (Timur Born) on DPReview.com looked a little deeper into the AF frame behavior and made some really interesting comments on a discussion we had on DPR. See the discussion here. Timur is the guy who wrote an excellent E-M5 “setting up” article on DPR. Timur also did his own summary on the E-M5 Auto Focus behavior and you can see his thoughts here.
In this article I only talked about S-AF, in a next I will have a closer look at tracking plus C-AF.
Siegfried