E-M1 - idiots guide to focusing modes needed!

Bear in mind that I come from a DSLR background - I am am still trying to get to grips with the whole CDAF thing. So, perhaps some of you can give me some real world examples of what and when to use.

1. Why would I ever use the entire focus grid and let the camera choose which point to use? I have always just used one centre point with the focus and recompose method. It has always baffled me why cameras have so may, esp the new CaNikons.

2. Face detect - I get this, it works well with my Fujifilm X10 and so should work even better with the M1. With this enabled, does it take priority over AF point? So if it sees a face will it lock onto that, regardless of anything else? Is it possible to assign a function button to toggle face detect on and off? I was considering changing the setting of P mode on the dial so that it stands for People - and basically have that as default mode for portraits and candids. Maybe a simple toggle on/off would be better?

3. C-AF - I never used this with my previous cameras, but now am working with stage shows where people move around the performance space so would like to give it a go. What is difference between CAF and tracking? the user manual does nothing to enlighten here. Would love to hear from mirrorless experts here.

Thanks

J

Jay Jenner said:

Bear in mind that I come from a DSLR background - I am am still trying to get to grips with the whole CDAF thing. So, perhaps some of you can give me some real world examples of what and when to use.

1. Why would I ever use the entire focus grid and let the camera choose which point to use?

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You wouldn't. That's an option for "dummies".

Jay Jenner said:

I have always just used one centre point with the focus and recompose method. It has always baffled me why cameras have so may, esp the new CaNikons.

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The focus-and-recompose method will give you systematic focus errors. See link below. The errors aren't always large enough to matter but they sometimes are and it's a good idea to avoid focus-and-recompose when you can.

http://www.visual-vacations.com/Photography/focus-recompose_sucks.htm

Jay Jenner said:

2. Face detect - I get this, it works well with my Fujifilm X10 and so should work even better with the M1. With this enabled, does it take priority over AF point? So if it sees a face will it lock onto that, regardless of anything else? Is it possible to assign a function button to toggle face detect on and off? I was considering changing the setting of P mode on the dial so that it stands for People - and basically have that as default mode for portraits and candids. Maybe a simple toggle on/off would be better?

Click to expand...

I don't use face detect. Hopefully others will help you with this.

Jay Jenner said:

3. C-AF - I never used this with my previous cameras, but now am working with stage shows where people move around the performance space so would like to give it a go. What is difference between CAF and tracking? the user manual does nothing to enlighten here. Would love to hear from mirrorless experts here.'

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The difference between C-AF with and without tracking is that with tracking, the camera tries to help you by moving the AF frame around so that it stays on what the camera takes to be the subject.

Thanks - so with CAF I would keep the camera pointed at the subject, but with tracking I could leave it - for instance focused on the stage and the focus would follow subject within the frame? I got nothing to try it on at home -- cat moves too fast.

Cheers

Jay Jenner said:

Thanks - so with CAF I would keep the camera pointed at the subject, but with tracking I could leave it - for instance focused on the stage and the focus would follow subject within the frame? I got nothing to try it on at home -- cat moves too fast.

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Yes. And you can try it at home even without the cat's cooperation. Focus on something and then move the camera so as to change the framing a bit. If things work as they should, the AF frame will then move around within the frame so as to stay on the target you first chose.

Aha, thats cool -- thanks! I look forward to trying that out on stage.

Jay Jenner said:

Bear in mind that I come from a DSLR background - I am am still trying to get to grips with the whole CDAF thing. So, perhaps some of you can give me some real world examples of what and when to use.

1. Why would I ever use the entire focus grid and let the camera choose which point to use? I have always just used one centre point with the focus and recompose method. It has always baffled me why cameras have so may, esp the new CaNikons.

2. Face detect - I get this, it works well with my Fujifilm X10 and so should work even better with the M1. With this enabled, does it take priority over AF point? So if it sees a face will it lock onto that, regardless of anything else? Is it possible to assign a function button to toggle face detect on and off? I was considering changing the setting of P mode on the dial so that it stands for People - and basically have that as default mode for portraits and candids. Maybe a simple toggle on/off would be better?

3. C-AF - I never used this with my previous cameras, but now am working with stage shows where people move around the performance space so would like to give it a go. What is difference between CAF and tracking? the user manual does nothing to enlighten here. Would love to hear from mirrorless experts here.

Thanks

J

--
http://www.flickr.com/photos/jdloudon/

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1. rarely if ever. i have it set for a preset ("myset") when i want to take fast, sneaky, "street" photos [full or reduced-matrix focusing, AF tracking on, 3-shot burst, moderately fast shutter priority]

90% of the time i focus-recompose from center point.

2. yes, it takes precedence over any spot or group focusing. you can also set a mode to have face-detect on, and save it as a preset ("myset"), which you can toggle on or off using a Fn button.

it works well. if im taking still life it doesnt get fooled thinking an apple or stop sign is a face. rarely do i need turn it off.

3. the manual *is* terrible about making this distinction. im in S-AF 90% of the time but i can take a stab: C-AF continually re-acquires focus. so if your subject is moving fore<-->aft, it's very necessary. or wide-open portrait where subject movement of camera might throw an eye OOF.
you need to keep your focus point over the object, and MANUALLY TRACK [=PAN] with object if theyre moving left right..... its as if you repeatedly half-press the shutter button.
TRACKING mode will automatically track the object across the frame if your camera is fixed, or you dont want to pan. problem is its not 70% perfect, in initial focus lock and/or maintaining the track.
thus, im almost always in S-AF. sometimes in C-AF. and rarely in C-AF TR (only used for street preset like #1)

Jay Jenner said:

1. Why would I ever use the entire focus grid and let the camera choose which point to use? I have always just used one centre point with the focus and recompose method. It has always baffled me why cameras have so may, esp the new CaNikons.

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Most of the time, and on most cameras, it's indeed pretty useless.

But not on my 5DIII IMHO. There are two reasons why :

1) the automatic AF point selection is 100% reliably predictable, because it's totally dumb : it's always going to pick the closest object within the AF points frame. Now you may think it's daft, but it means you can always predict where it's going to autofocus.

2) on the 5DIII and 1DX, you can trigger different AF modes with different buttons. So for example, you can use user-selected single AF point with the shutter release, and auto AF point selection with the AF-ON button.

The combination of both is IMHO a total win : in fast paced situations, if the object I want to focus on is the closest, I simply press AF-ON, meaning that I've saved time moving the AF point around or focusing and recomposing. If it isn't the closest, I focus normally.

This actually is something that I'd like to see on live view cameras with face detection. I like the fact that on Olympus cameras, you can live it on, and if it doesn't find a face, it will use the selected AF point. But as soon as it detects a face, there is no way to tell the camera not to focus on the face, but on the selected AF point. What I'd really like to see is the ability to use the usual AF mode with, for example, the shutter release, leave face detection on, but only trigger face detection AF when pressing another button (ex : the AFL/AEL button), not the shutter release. Also, since the E-M1 uses PDAF, it's able to "map" the phase AF point area and could therefore also behave like the Canon, i.e. always select the closest object.

Good info, thanks. Did not realise that about Canon -- makes sense - 100% predictable - thats what you need. So PDAF can tell what is closer, but CDAF cannot. It seems the Olympus deployment of both is a bit odd and I hope that the next incarnation of the camera can combine both types of technology better.

Going back to 100% predictable - I feel that so far that is what is missing from the M1, for me at any rate. When shooting with the old E1/E3/E5 - whilst not as smart as new cameras I felt like I was always sure exactly what it was doing and what I was going to get from the shot. It'll take me a while to get totally comfy with the M1 I reckon. However I knew that might be the case, stepping out from my comfort zone, but thats sometimes what needs to be done to gain the full benefits from new technology.

It was very nice though to wander around town yesterday with the camera on a strap - and be virtually unaware of its weight and presence! Which was never the case with the E5/12-60 combo.

Jay Jenner said:

Good info, thanks. Did not realise that about Canon -- makes sense - 100% predictable - thats what you need. So PDAF can tell what is closer, but CDAF cannot.

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Perhaps Panasonic's DFD system may also be able to map distance over the whole picture.

Jay Jenner said:

Going back to 100% predictable

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I think that predictability is one of the most important things to have with an automatic behaviour - some of them try to be too intelligent for their own good. It reminds me of my former D700's metering. In matrix mode, I couldn't predict how much exposure compensation would be needed - it did not correspond to a rough average of highlight / shadows in the scene (problem solved using other metering mode). With the 5DIII and its feeble 63 zone metering system that's a bit last week, it's dumb, and never quite get the exposure totally right, but very predictable, right down to the precise amount of exposure compensation I'll need to apply.

Of course now with Olympus, Sony and Panasonic cameras with EVF, you get live highlight warnings, so there isn't even a need to make a prediction.

Jay,

On the E-M1, there is a setting in the AF/MF menu named "C-AF Lock" with four options:
Off, Low, Normal, High.

When you are in C-AF mode with this enabled, it tells the camera not to constantly change focus if something other than the subject passes across the frame. The three options determine the sensitivity threshold, i.e. the time length for a temporary interruption to be ignored, I think.

As for your other questions. The focus grid is really designed for street photographers to take quick snapshots using the shutter trigger on the LCD screen. They simply tap on a square to take a shot without the subject realising that they are doing it.

Face detection works very well when you are actually taking a portrait of someone. It tracks your subject's left/right eye and maintains sharp focus even when your subject turns their head a little (which can soften the image if you use normal AF points). The rest of the time it should be turned off because it could see phantom faces in objects and cause you to misss a shot sometimes. Yes, you can assign the function to a MySet or a program mode on the Mode dial.

There are so many ways to auto-focus on the E-M1. I take a lot of action shots (mostly musicians on stage). I'm almost always on S-AF+MF and I use the touch screen a lot. I figure if you have still life, it doesn't really matter what mode you use, but otherwise, you need something that will work quickly.

Here are three basic ways I take action shots. Focus and recompose is not any of them.

1. Touch shutter. Just select what I want in focus and it takes the shot right away. Done. While I like this method, I feel that it's not quite as good as the next method.

2. Touch focus + wait + click shutter. Basically, I compose the shot in my head. I decide, for instance, let's make a shot with the face in focus, in the top left of the screen, when the guitarist is doing X. I tap the touchscreen to set the focus point to that point, and then I put the camera to my eye and then wait for the guitarist to get in my focus point. Then I click the shutter. The advantage to the first method is that I can reuse my focus point for the next set of shots, whereas using the touch shutter resets the focus point after each picture.

3. Eye detect. This is only really useful in very specific situations. For instance, if a singer is at the microphone and stays still long enough that my eye detect can register. It is very useful in one specific situation, which is a drummer shot. Your average drum set has stands and cymbals all over the place and it's hard to get just the face in focus, and it's often hard to have enough precision with the touch screen to get just the right thing in focus. If they stay still for a second, that eye detect can really save the day. Eye detect is also really useful for getting singers because if you just let the camera pick the AF point, it would just focus on the mic stand. For singing drummers, it pretty much is a live saver.