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DerekW
5th March 2017, 10:56 PM
I heard the benefits of Back Button Focusing (BBF) described at the Marwell Zoo visit but I did not pay sufficient attention as to how one sets it up, I thought I did at the time, but I was overhearing the conversation so did not properly remember. The description of how to Focus using the Fn2 button and then releasing the shutter after changing the composition (but holding the focus selected by the Fn2 button) seemed to be a very useful technique.

Please can someone describe the settings I have to make to use this option.

If one does not always want to use BBF how does one switch to the shutter release button focussing.

Thanks for any info. - If you are aware of a thread in the forum that describes the method please point me to it.

pdk42
5th March 2017, 11:12 PM
I don't have my camera in front of me right now, but the principle is this (this is for E-M1, but it must be very similar for the mark II since I set one up at a demo day in about 20 seconds):

Gears menu A (AF/MF) -> AEL/AFL -> S-AF ( or C-AF if you prefer that)
- Select mode 3

Gears menu B (Button/Dial) -> Button Function
- Choose your preferred button for BBF and assign it to AEL (on my E-M1 I use the AEL button itself)

To swap back - well, best to setup two My Sets (or custom modes on the mark II).

Phill D
6th March 2017, 09:11 AM
Is this something that you can use that odd lever for? I.e. normal shutter button focussing until you flip the lever and then go to back button focus. Flip the lever back to return to normal? It would be really good if it could be set up like that. Well for me anyway.

TonyR
6th March 2017, 09:38 AM
I heard the benefits of Back Button Focusing (BBF) described at the Marwell Zoo visit but I did not pay sufficient attention as to how one sets it up, I thought I did at the time, but I was overhearing the conversation so did not properly remember. The description of how to Focus using the Fn2 button and then releasing the shutter after changing the composition (but holding the focus selected by the Fn2 button) seemed to be a very useful technique.

Please can someone describe the settings I have to make to use this option.

If one does not always want to use BBF how does one switch to the shutter release button focussing.

Thanks for any info. - If you are aware of a thread in the forum that describes the method please point me to it.

What are the benefits of BBF?

TonyR
6th March 2017, 09:53 AM
Sorry. Duplicate.

Clockwork Donkey
6th March 2017, 09:57 AM
Well apart from the focus and recompose benefit, there is a great advantage of using BBF for landscape and still life/product/table top photography. In those circumstances a tripod is usually used along with live view. BBF allows you to fucus on your selected point (for maximum depth of field for instance) and then operate the shutter without risk of the focus point changing.

TonyR
6th March 2017, 09:57 AM
OK, thanks.

DerekW
6th March 2017, 10:11 AM
Paul

Thank you - I think I have got it ! - I had a MK I available to set it up on initially and then was able to navigate (fumble) over the settings to the MkII.
The differences in the menu structure between the two models are quite dramatic

Zuiko
6th March 2017, 10:57 AM
Back button focusing is invaluable to me because I can no longer maintain a half press on the shutter button to lock focus without inadvertently actually firing the shutter.

andym
6th March 2017, 11:23 AM
What are the benefits of BBF?

With the camera set in manual focus mode3 you have the advantage of being able to use full manual focus which is great coupled with manual focus assist and have the advantage of full auto focus on the back button.

Well that's how I use it.

drmarkf
6th March 2017, 01:39 PM
There are any number of guides and tutorials on the interwebs about BBF, but this one's quite good: http://www.digital-photo-secrets.com/tip/4374/back-button-focus/

I actually use FRONT button focus for this on my E-M5ii because I'm a left-eye shooter and the camera body's so small that my right eyebrow gets in the way of my thumb if I use the AEL/AFL button by the viewfinder. I set it to the button on the front panel, and use my right 4th finger for it (I use AEL/AFL for a MySet).

There's plenty of room to have it set to Fn1 on the E-M1 which is fine for the right thumb.

pdk42
6th March 2017, 02:28 PM
There are any number of guides and tutorials on the interwebs about BBF, but this one's quite good: http://www.digital-photo-secrets.com/tip/4374/back-button-focus/

I actually use FRONT button focus for this on my E-M5ii because I'm a left-eye shooter and the camera body's so small that my right eyebrow gets in the way of my thumb if I use the AEL/AFL button by the viewfinder. I set it to the button on the front panel, and use my right 4th finger for it (I use AEL/AFL for a MySet).

There's plenty of room to have it set to Fn1 on the E-M1 which is fine for the right thumb.

I do the same on the Pen-F. The rear Fn2 button is poorly placed and in any case it's handy to keep its default action of switching between EVF and rear screen. To avoid confusion on my E-M1 I have both the back button and one of the front buttons mapped to AF - that way I won't struggle swapping between them.

drmarkf
6th March 2017, 03:14 PM
... To avoid confusion on my E-M1 I have both the back button and one of the front buttons mapped to AF - that way I won't struggle swapping between them.

Yes, I can see that could be a good idea, although I like to use all the buttons available on the E-M1 for useful individual things.

On Saturday I had an afternoon shooting with both cameras at our local rugby club (who, incidentally, host meetings of our camera club): I managed not to get confused between front and rear button focusing!

I'd done this before with 2 M1s, one with the 40-150 pro + t/c, and the other with the Panny 35-100 f2.8 (for closer action). I'd found both lens setups reasonably good for acquiring and holding focus - not DSLR standard, but perfectly usable. This time, with the Panny on the M5ii it really showed up the better CAF of the M1, and I gave up trying with the 5ii after a while.

Have you tried using the Pen-F for this sort of action shooting?

The M1/40-150/tc is very competent in the good light we had, and the main issues were the photographer's incompetence at keeping up with how fast the backs at this level move the ball around (!), plus the time the mki takes to clear its buffer. The mkii should be a lot better in this regard, as well as having less screen blanking during fast high-speed shooting.

I'm just about to finish processing some images and I think I'm satisfied enough to post a few in Foto Fair in a mo'!

Crazy Dave
6th March 2017, 03:53 PM
This may of interest/adaptable

http://www.lessgearmorephotos.com/back-button-autofocus-olympus-om-d-e-m5/

David

Ricoh
6th March 2017, 05:47 PM
Both my em5 and gx7 are set up this way. Gx7 has a bigger button. Obviously someone in their design team knows something about anthropometrics. My favoured way of shooting is in the zone, viz zone focusing using a RF.

Cerebus
6th March 2017, 08:35 PM
Back button focusing is invaluable to me because I can no longer maintain a half press on the shutter button to lock focus without inadvertently actually firing the shutter.

I have the same problem with the E-M1.

On the E-M10II it's no problem though.

Maybe the shutter button on the E-M1 is a bit too sensitive?

Clockwork Donkey
6th March 2017, 08:49 PM
I've lost count of how many inadvertent shots I have taken of my feet!

Mrs T
6th March 2017, 08:57 PM
I've set mine up on the E-M1 II and find it very useful. I used the menu options and it's on my AEL button which is much better placed than on the mark I.

RobEW
7th March 2017, 08:11 AM
Back button focusing is invaluable to me because I can no longer maintain a half press on the shutter button to lock focus without inadvertently actually firing the shutter.

That's a point which seems rather overlooked by camera designers and enthusiasts. Lots of people, and most of us as we get older, can experience difficulty with tactile sensitivity, proprioception, digital dexterity and digital control. And some of the camera controls make high demands on all these capabilities. Learning to use a particular camera fluently seem in some ways as demanding on such capabilities as learning to play a clarinet - perhaps more so in that lots of the controls on a camera are rather tiny, rather close to each other, and not very tactile. And also because when your eye is to the EVF, you can't see what your fingers are doing. Some people also have relevant medical problems such as tremor or arthritis.

One example: with my fingers, on the E-M5 II, I find I can push "that odd lever" down (from position 1 to position 2) while looking through the viewfinder, but - unless the screen is folded out - have to pull the camera away from my eye and look closely to push it back up again to position 1. On the E-M1 there is more room and I can push it up and down by feel alone.

Fortunately, the E-M5 II and E-M1 (and possibly other OM-Ds I don't have) are very configurable, and have a number of controls - e.g. the rotating dials - with good ergonomics.

drmarkf
7th March 2017, 09:19 AM
All manufacturers face a trade-off between usability, which mainly means hard buttons/dials/levers rather than menus (even configurable 'quick' ones), and body size.

For Olympus the watershed lies somewhere between the M5ii and the M1: the M5ii's design brief for me featured compactness as a major point, while usability came a lot higher with the M1. Although you can set the 5ii up to be very convenient for a single application (like landscape, or street, or sports/wildlife) it's much more of a hassle than the M1 to do so for several of these, and I end up having to use menus to complete the setup for one or the other.

This is the basis of some of the criticism both iterations of the M1 have received about their size: the ii body is around the same size as the full frame Nikon D750, for example. Now, in many ways the ii packs as much or more in to its body as the Nikon, including decent battery life, and it needs a lot of 'hard' controls to be able conveniently and reliably to access its much greater configurability. There's a minimum body size to achieve that.

RobEW
7th March 2017, 11:09 AM
There are any number of guides and tutorials on the interwebs about BBF, but this one's quite good: http://www.digital-photo-secrets.com/tip/4374/back-button-focus/

I actually use FRONT button focus for this on my E-M5ii because I'm a left-eye shooter and the camera body's so small that my right eyebrow gets in the way of my thumb if I use the AEL/AFL button by the viewfinder. I set it to the button on the front panel, and use my right 4th finger for it (I use AEL/AFL for a MySet).

There's plenty of room to have it set to Fn1 on the E-M1 which is fine for the right thumb.

Thanks - a great and well explained article.

Can I ask a question for clarity. The article describes assigning a function called "AF ON" to a button, and redefining the shutter half way down button action to do nothing.

Can you (or anyone) say exactly what function you assign to the relevant button (e.g. the one labelled AEL/AFL on the OM1).

For someone using the AEL/AFL button for back button processing, do they leave the AEL/AFL button assigned to the AEL/AFL service but then redefine the AEL/AFL service to be something like S3/C4/M3 ?

= = =

P.S.

I have to say, as someone new to "proper" digital photography, and whose last experience of "proper" photography involved a 35 mm film SLR, I'm mystified why these modern mirrorless digital cameras bundle together the various notions of:
- gaining and locking focus,
- measuring and locking exposure, and
- triggering the shutter
on to too few controls.

If I were designing a user experience from scratch, I think I'd want to focus, then lock focus, then maybe recompose a bit, then measure exposure with a WYSIWYG view in the EVF, then optionally adjust this with exposure compensation, which would then lock the exposure, and then trigger the shutter. I find myself using exposure compensation and HDR a lot. HDR is utter magic, and can work very well hand held!

PeterBirder
7th March 2017, 09:51 PM
Thanks - a great and well explained article.

Can I ask a question for clarity. The article describes assigning a function called "AF ON" to a button, and redefining the shutter half way down button action to do nothing.

Can you (or anyone) say exactly what function you assign to the relevant button (e.g. the one labelled AEL/AFL on the OM1).

For someone using the AEL/AFL button for back button processing, do they leave the AEL/AFL button assigned to the AEL/AFL service but then redefine the AEL/AFL service to be something like S3/C4/M3 ?

= = =

P.S.

I have to say, as someone new to "proper" digital photography, and whose last experience of "proper" photography involved a 35 mm film SLR, I'm mystified why these modern mirrorless digital cameras bundle together the various notions of:
- gaining and locking focus,
- measuring and locking exposure, and
- triggering the shutter
on to too few controls.

If I were designing a user experience from scratch, I think I'd want to focus, then lock focus, then maybe recompose a bit, then measure exposure with a WYSIWYG view in the EVF, then optionally adjust this with exposure compensation, which would then lock the exposure, and then trigger the shutter. I find myself using exposure compensation and HDR a lot. HDR is utter magic, and can work very well hand held!

Hi Rob.
If you go to the link in post #14 you will find instructions on how to set up OM-D cameras for back button focussing. The link Mark gave was written by someone who uses Canons so it covers the priniples but not the camera specific settings.

Re your P.S.
Your "ideal" view of how things should operate is really just how a manual film SLR has to be operated. Your OM-D's are highly configurable devices with a host of functions and features which you can choose to use (or not use) in various combinations to make the camera perform more to your personal needs/liking and depending on the type of photography you do and the conditions in which you do it.
If you use manual mode you can set the camera to behave just like a "simple" film SLR and if I remember correctly member David M has his cameras set to replicate his OM film cameras. However, the development of very fast and accurate Auto Focus for example, enables you to speed up the process of taking a photo making it easier to "catch the moment". Using the different AEL/AFL options enables you to chose when the exposure is locked after the focus has been achieved automatically. Using the apparent exposure in the EVF to set your exposure is not going to be very accurate but you have a number of options available. Firstly you can choose the ESP metering which measures the brightness using data from the whole frame and on the Olympus cameras works pretty well for the majority of cases but you also have the options of Centre Weighted and Spot modes for more difficult scenarios. Best of all you have the Histogram display which you can set to appear in the bottom of the EVF and will show you if you have under or over exposed areas, particularly pesky highlight spikes at the right hand end and enable you to see the effect of diialing in exposure compensation.
As far as focusing and recomposing is concerned there are now a couple of features in the cameras which I at first dismissed as gimmicks but on trying them found actually work surprisingly well. The first is the ability to use the touch screen with your thumb to move the focus box whilst looking through the EVF. The second is the "touch and shoot" function in liveview mode (which I normally hate) to compose your picture and then touch the point you want to be the main focus which then virtually instantly auto focuses, sets exposure and then fires the shutter. It works surprisingly well.

Many of the settings in the seemingly endless menus you will only need to ever set once and by experimenting with different configurations you will arrive at a few combinations which suite your main types of photography and can be set as Mysets for instant recall as needed.

Regards.*chr

Ricoh
7th March 2017, 10:37 PM
Thanks - a great and well explained article.

Can I ask a question for clarity. The article describes assigning a function called "AF ON" to a button, and redefining the shutter half way down button action to do nothing.

Can you (or anyone) say exactly what function you assign to the relevant button (e.g. the one labelled AEL/AFL on the OM1).

For someone using the AEL/AFL button for back button processing, do they leave the AEL/AFL button assigned to the AEL/AFL service but then redefine the AEL/AFL service to be something like S3/C4/M3 ?

= = =

P.S.

I have to say, as someone new to "proper" digital photography, and whose last experience of "proper" photography involved a 35 mm film SLR, I'm mystified why these modern mirrorless digital cameras bundle together the various notions of:
- gaining and locking focus,
- measuring and locking exposure, and
- triggering the shutter
on to too few controls.

If I were designing a user experience from scratch, I think I'd want to focus, then lock focus, then maybe recompose a bit, then measure exposure with a WYSIWYG view in the EVF, then optionally adjust this with exposure compensation, which would then lock the exposure, and then trigger the shutter. I find myself using exposure compensation and HDR a lot. HDR is utter magic, and can work very well hand held!
If you were to say you enjoy street photography, I'd recommend zone focusing. There isn't a digital camera on the planet that can out pace a zone focused camera, even one back button focused.

RobEW
8th March 2017, 09:46 AM
Hi Rob.
If you go to the link in post #14 you will find instructions on how to set up OM-D cameras for back button focussing. The link Mark gave was written by someone who uses Canons so it covers the priniples but not the camera specific settings.



Thanks. I think I missed that link.



Re your P.S.
Your "ideal" view of how things should operate is really just how a manual film SLR has to be operated.

...


Regards.*chr

Maybe that's because the last time I did "proper" photography (rather than "point and click" photography) it was using a 35mm film camera (Oly OM2N) and maybe I still think in those ways and haven't changed my habits enough to fully exploit modern equipment.

It's interesting to reflect that in some circles one is expected to prove one's photographic virility by using manual (e.g. mode M) rather than automated (e.g. mode P) features for exposure, but the use of manual features for focussing is rather unfashionable.

Ricoh
8th March 2017, 05:52 PM
Thanks. I think I missed that link.



Maybe that's because the last time I did "proper" photography (rather than "point and click" photography) it was using a 35mm film camera (Oly OM2N) and maybe I still think in those ways and haven't changed my habits enough to fully exploit modern equipment.

It's interesting to reflect that in some circles one is expected to prove one's photographic virility by using manual (e.g. mode M) rather than automated (e.g. mode P) features for exposure, but the use of manual features for focussing is rather unfashionable.
Well it all depends whether you are happy with the silicon chip doing it for you, or you're more happy using the grey stuff. How many times has the Si chip focused on something other than you expected, and completely messed exposure because there was too much sky. This is the result of the designers catering for the happy snapper.

RobEW
8th March 2017, 08:54 PM
Thanks for pointers in this thread - very useful. I've done some more reading and experimenting, and getting to grips with it, and while doing so made my own notes. In case anyone is interested, I'm posting them here. If anyone is interested and has the patience to read it, and thinks I'm in some way mistaken, I'd be grateful to know.

:-)

= = =

Back button focus.

The idea is that without BBF, the system will refocus (if you’re in S-AF or C-AF or similar modes) whether you like it or not when you press the shutter half way down. With BBF, you can nominate a button (conventionally one on the back of the camera – hence the name) to use to initiate an auto-focus (instead of pressing the shutter half way down to do this). In conjunction with this you also disable the auto-focus action of the half way pressed shutter button. Then AF only happens when the BBF button is pressed.

The button usually chosen on E-M5 II is Fn1 (the button at the pivot point of the two-way lever). On the E-M1 the button in the same spot (inscribed "AEL/AFL") is also the default for this function. (Fn1 is elsewhere on the E-M1). I don't know about other Olympus bodies. For the rest of this note I'm assuming for the sake of example the Fn1 button on the E-M5 II.

The advantage is this: you can use BBF to acquire and lock focus, then you can recompose (or things can happen in the scene) but you can still continue to take one or more photos with the established focus. This is useful. E.g. when a bird is flying to and from a favourite perch, you can focus on the perch and then take exposures whenever the bird arrives. If you mis-time a shot and the bird isn’t there, you don’t find that it has focussed on something distant behind where the bird should have been.

The key thing is this. You don’t have the camera trying to autofocus for you just before each shot. It focuses when you tell it to, and not at other times.

BBF is thus more useful than going fully to MF. With BBF you can still use AF facilities, but you choose when it will do the AF rather than letting the camera choose for you (just before every shot). AF becomes your servant and not your master. (BBF can also be useful for someone who doesn’t have the tactile sensitivity or digital dexterity to hold the shutter button accurately half way down for some time – especially if wanting a sustained period of continuous auto-focus).

In the menu system, setting this up is a little complex.

The easy bit is assigning a button to initiate AF (easy apart from Olympus’s clunky nomenclature). You have to assign the service misleadingly named “AEL/AFL” to the button Fn1. Menu -> Custom Menu -> B. Button/Dial/Lever -> Button Function then from the pull down list of services beside Fn1, select “AEL/AFL” and hit “OK” button. (This service is assigned to this button by default when the camera is new or reset, so you may not need to do this).

Disabling the auto-focus service which is normally (in default settings) invoked when the shutter release button is pressed halfway down is a bit more involved. Menu -> Custom Menu -> A.AF/MF -> AEL/AFL provides a system for customising the “AEL/AFL” service. You provide three definitions of the service for it to store, because the “AEL/AFL” service has different effects depending on whether the camera is in S-AF, C-AF or MF focussing mode (sometimes abbreviated in this context to S, C & M). Each of these three definitions of the “AEL/AFL” service specifies three things: what you want to happen when the shutter button is pressed half way down, what you want to happen when it is pressed fully down, and what you want to happen when a button which invokes the “AEL/AFL” service (Fn1 in this case) is pressed. What happens can include a mixture of focussing actions and also exposure-metering actions. Once in the menu, for each of the three focussing modes (S, C & M) you don’t get a free choice of focussing and metering actions; instead you have a choice of up to four “AEL/AFL modes”, each of which provides a different combination of actions.


MODE 1
o AEL/AFL button toggles auto-exposure lock. [1] (file:///C:/Users/Rob/Documents/Camera%20settings.docx#_ftn1)
o Half pressed shutter button invokes AEL and S-AF or C-AF (if in S-AF or C-AF mode)
o Fully pressed shutter button takes a photo.


MODE 2
o AEL/AFL button toggles auto-exposure lock.
o Half pressed shutter button invokes S-AF or C-AF (if in S-AF or C-AF mode)
o Fully pressed shutter button takes a photo.


MODE 3(the mode typically selected for back button focus)
o AEL/AFL button invokes autofocus; if in C-AF focus mode it begins continuous auto-focussing; if in S-AF or MF focus modes, it does a single auto-focus.
o Half pressed shutter button provides AEL.
o Fully pressed shutter button takes a photo.


MODE 4 (only available with C-AF)
o AEL/AFL button begins continuous auto-focussing.
o Half pressed shutter button does nothing.
o Fully pressed shutter button takes a photo.

Thus assigning MODE 3 for any of S, C and F or MODE 4 for C will make the button assigned to AEL/AFL invoke focussing, and will prevent refocusing when the shutter button is pressed halfway down. (It will also, as a side effect, postpone the locking of exposure until the shutter button is pressed halfway down, or – in MODE 4 – fully down).

= = =

BBF when in MF mode (and using AEL/AEF MODE 3) is quite interesting. It allows you to use the autofocus facility in a controlled manner. This is in contrast to S-AF and C-AF modes where BBF eliminates potentially unwanted auto-focussing; in MF mode it offers help (upon request) by providing auto-focussing.


Personal thoughts:

1. Using BBF seems sensible to gain better control (though, in some contexts, at the expense of speed). I don’t do sports or street photography so there’s usually time to make considered judgements about focus, exposure etc. Composition takes more time than technicalities.

2. I think you can sometimes prevent an unwanted AF just prior to shutter release if you jab the shutter button down without pausing at the halfway point. However it sometimes still interrupts to do an unwanted AF. I think it helps if you select the options to give shutter priority over focussing: Menu -> Custom menu -> C: Release -> Rls priority S = ON & Rls priority C = ON. However this doesn’t seem to be reliable and I’ve not seen it recommended. I shall ignore this possibility.

3. The button usually chosen for BBF on OM-D is the button at the pivot point of the two-way lever (known as Fn1 on the E-M5. On the E-M1, it is known simply as the AEL/AFL button, as Fn1 is elsewhere). This is workable for me on the E-M1, but not a very useful switch for me on the smaller E-M5 II, as – if I’m looking into the viewfinder – my spectacles obstruct the path of my finger to Fn1. If I adopt BBF then I want the button to be in about the same place on both cameras. For the moment I’ll stick with this position and see whether I can get used to finding it fluently on the E-M5 II.

4. I should explore the interaction between BBF settings and the two other metering modes not explicitly mentioned; “C-AF TR” and “S-AF MF”. I’m guessing that if you’re in “S-AF MF” mode it treats that as S-AF for the purpose of choosing one of these three definitions of “AEL/AFL”, and that if you’re in “C-AF TR” it treats it as “C-AF” for this purpose.

5. Back-button focus in C-AF mode seems similar to Full-time AF. The latter doesn’t require a button to be assigned.

6. I mainly use “S-AF MF”. It would be nice if any time I used the focus ring the camera would automatically switch to MF mode and also lock the focus. There’s a menu entry called “MF clutch” which is poorly described in the manual but may be something to do with this. It doesn’t seem to make any difference I can discern so far on my camera. Annoyingly the focus ring is ignored unless you’re in “MF” or “S-AF MF” modes, which feels (to an old SLR user) like emasculation.

7. MODE 4 appears to be a slightly weaker version of MODE 3. I don’t quite understand the purpose of MODE 4. (I suppose MODE 4 compares to MODE 3 in the same way as MODE 2 compares to MODE 1; the difference concerns when it fixes light meter readings, so irrelevant to the topic of focussing).

8. Most of the above complexity could be avoided if we could just make Fn1 toggle between MF and whatever focussing mode was previously specified. You could acquire focus either using half-pressed shutter button (or full time AF), then when it’s nicely focussed you could switch to MF, which then allows you to make fine adjustments with the focus ring (with peaking & magnification), and also prevents the shutter button from subsequently usurping control over focus.

9. Why the AEL/AFL MODEs offer such weird choices and trade-offs between controlling the sequencing of exposure measurements and focussing actions is a great mystery. There appears to be no way to control the sequencing of focussing and exposure measurement locking apart from the strange AEL/AFL modes. I.e. there is no provision for “back button metering” alongside back button focussing. BBF is one way of escaping point-and-click style focussing, but it requires you to adopt a point-and-click approach to metering. Weird stuff Olympus.


[1] (file:///C:/Users/Rob/Documents/Camera%20settings.docx#_ftnref1) Auto-exposure lock is a different topic, but this is what I think it does. The AEL service is toggled on and off by alternate presses of the button. When you invoke AEL, then the exposure meter measures the light according to the various exposure parameters (e.g. metering mode), sets any exposure-related settings which are under its control (e.g. exposure time, lens aperture, ISO level), and then stops metering. The “lock” is indicated by an “AEL” symbol in the viewfinder or rear screen display. When you release AEL, then metering resumes and any exposure-related settings which are under automatic control will be dynamically adjusted according to the (possibly fluctuating) light levels detected.

drmarkf
8th March 2017, 10:51 PM
I think people often use the front panel button for 'BBF' on the M5ii because using any of the top panel buttons needs you to perform multi-finger or multi-button gymnastics, and there are times when you need to press the shutter and focus buttons at the same time.

pdk42
9th March 2017, 12:30 AM
I think people often use the front panel button for 'BBF' on the M5ii because using any of the top panel buttons needs you to perform multi-finger or multi-button gymnastics, and there are times when you need to press the shutter and focus buttons at the same time.

That's certainly true of the Pen F too.

RobEW
9th March 2017, 07:30 AM
The button which is otherwise used for "Depth of field preview"?

As I've been trying out BBF, I'm finding it sometimes a boon and sometimes a burden. Learning to use a camera fluently is - in digital dexterity terms - a bit like learning to play the clarinet. You need some precision, and also good tactile feedback to detect whether your finger is actually on a button.

The shutter button is ergonomically very convenient for focussing, but unfortunate that it invokes a refocus when you take a photo. A "fast press" option (which bypasses the half pressed actions) would be really nice. Maybe I'll try using BBF on the video button (which I don't often use, and is in about the same place on E-M1 & E-M5 II). Or maybe I'll try using BBF in MF and standard focussing in S-AF.

TonyR
9th March 2017, 08:51 AM
RobEW,

Great write-up but can I just point out that the Fn1 button is the one on the right shoulder on the back of the camera whereas the button at the pivot point of the lever is called the "AEL/AFL" button.

I'm not quite sure how that affects what you have said but I'm going to give it a try.

I used BBF on the E-M1 for a while for C-AF but actually found it changed the way the AF worked in a bad way. To get the E-M1 C-AF to be reasonably accurate, you had to start shooting at the same time as the initial C-AF focus acquisition so AF on half press of the shutter was better. Let's hope the MkII doesn't suffer from similar issues.

Phill D
9th March 2017, 09:28 AM
Currently I just half press focus and then recompose to shoot. If the exposure needs a tweak then I'll just tweak the exposure compensation. I've always done it that way from the year dot so changing will take a bit of persistence but I'll definitely give this a try. As a general question is there anything wrong with what I've always been doing?

RobEW
9th March 2017, 10:55 AM
RobEW,

Great write-up but can I just point out that the Fn1 button is the one on the right shoulder on the back of the camera whereas the button at the pivot point of the lever is called the "AEL/AFL" button.

I'm not quite sure how that affects what you have said but I'm going to give it a try.

I used BBF on the E-M1 for a while for C-AF but actually found it changed the way the AF worked in a bad way. To get the E-M1 C-AF to be reasonably accurate, you had to start shooting at the same time as the initial C-AF focus acquisition so AF on half press of the shutter was better. Let's hope the MkII doesn't suffer from similar issues.


Well spotted. In fact it's a discrepancy. On the E-M1, Fn1 is on the chamfered corner near the right carrying-strap eyelet, and the button labelled AEL/AFL is in the pivot of the lever. On the E-M5 II, the button in the pivot of the two way lever is labelled Fn1 and by default is assigned to the AEL/AFL service. The E-M5 II has no button in the position of the E-M1's Fn1.

I've corrected my post to clarify this.

RobEW
9th March 2017, 11:02 AM
Currently I just half press focus and then recompose to shoot. If the exposure needs a tweak then I'll just tweak the exposure compensation. I've always done it that way from the year dot so changing will take a bit of persistence but I'll definitely give this a try. As a general question is there anything wrong with what I've always been doing?

I'm no expert, but I'd say if this works for you then it's fine. I use that method quite a lot as well. (I find focus and recompose is quicker than using the arrow keypad to move the focus point). It may need you to keep your finger on the shutter halfway down for possibly quite some time (e.g. if you're waiting for the subject to improve - e.g. for a standing bird to turn around). And if getting exact focus has been a bit painstaking and slow then you might want to retain that focus for several shots, and BBF would allow that.

drmarkf
9th March 2017, 11:31 AM
BBF combines well with tap-screen-to-focus for off-center subjects in street photography, especially when you want to have a small aperture (when zone focusing won't do).

You frame the scene and tap to focus in one go, then shoot when you like including on burst mode. If the subject moves a little you can refocus immediately with BBF, and if they move a lot you just tap them on the screen again.

If you have focusing on the half-press you have to reframe every time, which wastes ages and risks drawing the subject's attention to you.

This is with the screen flipped out like a TLR.

You do have to know how far from the centre the focus points spread, and in my experience tap focusing works better with the E-M1 than the M5ii, not surprisingly. Both are a bit better than the X70 Fuji (and all 3 enormously better than the A7Rii, which hasn't even got a touch screen...). I might add that the best piece of kit for doing this was my old Panasonic GM1, which focused frighteningly fast, very reliably, and in very low light, but it didn't have a tilt screen.

RobEW
27th March 2017, 09:44 AM
Quick footnote-style question on this discussion. Does anyone know how BBF interacts with other ways of taking photos such as the use of the rear screen, or the use of remote shutter release cables, or - of particular interest to me - the use of the Olympus Share app on a phone to trigger the shutter. In cases like these where there is no "button half down" state, does the a last moment refocus get imposed on us whether we like it or not?

RobEW
1st November 2017, 05:23 PM
...

8. Most of the above complexity could be avoided if we could just make Fn1 toggle between MF and whatever focussing mode was previously specified. You could acquire focus either using half-pressed shutter button (or full time AF), then when it’s nicely focussed you could switch to MF, which then allows you to make fine adjustments with the focus ring (with peaking & magnification), and also prevents the shutter button from subsequently usurping control over focus.



I was just revisiting my own write-up and realise that no-one picked up on this point.

I've just tested, and find that if I set a button to "MF", then it actually toggles between MF and whatever focussing mode was previously in effect.

Using this it seems easy to obtain all the benefits of back button focus with extra flexibility, fewer side effects and none of the complexities.

I can press shutter half way down when I want to establish an autofocus and then switch to MF which will precent any later autofocus occcurring when I actually take the photo. This also gives me the opportunity to tweak the established focus using the lens ring (supported by peaking etc); the extra flexibility. If I hit the MF button again I revert easily to normal auto-focussing protocols without having to devle into menues or retrieve a MySet. No need to mess with the labyrinthine AEL/AFL modes at all.

Are there any downsides or limitations to this method? It seems so much easier.

RobEW
4th April 2018, 01:29 PM
I'm still doing this and find it more useful (for my purposes) than back button focus.

I have Fn2 (on the E-M1 classic) set up to toggle between MF and whatever focus mode was set prior. And I have AEL/AFL set to S1/C2/M3 so that when I am in MF mode, the AEL/AFL button can be used to get an autofocus (though - being a bit of a dinosaur - I tend more often to use the manual focus ring, supported by peaking).

Does BBF offer anything better? I suppose it offers a subset of what I do but without using the Fn2 button.

RobEW
26th April 2019, 11:29 PM
A footnote to this. Since writing it I have obtained lenses with a AF/MF switch (PL 15 f/1.7) and with MF clutch (Oly 12 f/1.8).

Initially I wondered about using Fn2 for something else when one of these was mounted, but decided not to as I prefer to have a consistent meaning for my buttons irrespective of what lens is mounted. I simply ignore the extra features on the lens.

More recently I've obtained a (used) 12-100 f/4 and am finding it virtually never leaves the camera, so I thought I'd revisit that decision.

However after a bit of experimentation I have discovered that the "M3" selection (which tells the AEL/AFL button to be an AFL button when the camera is in MF mode) is ignored when the lens itself specifies MF (whether through a switch or a clutch).

If you want the AEL/AFL button to be usable to grab a quick auto-focus when in MF mode, then you have to specify MF mode via the camera, not via the lens.

So for my patterns of usage, I will continue to use Fn2 to toggle between AF and MF, and (when in MF mode) use AEL/AFL to grab a quick auto-focus. And - for my patterns of usage - any MF clutch or MF switch on a lens is not adding value.

bigsambwfc
29th April 2019, 06:50 PM
I tried BBF on my mk2 programmed to the AEL/AFL button with not much success,because I found the button too stiff causing the telephoto lens to move, thus blurred images, went back to normal shutter half press pump system.

SCoastPhotographer
9th May 2019, 06:26 PM
Sometime ago a friend set up my OMD EM 1 II for BBF, using the AEL/AFL for bbf. My question is, what settings to I need to change to revert back to the "normal" way of focussing, ie half a press of the shutter release button, with AEL/AFL returned to its usual role. Can someone help please? Thanks.

TonyR
9th May 2019, 06:39 PM
Gears->A1->AEL/AFL set to mode1 for either/both S-AF and or C-AF.

SCoastPhotographer
9th May 2019, 06:54 PM
Thanks Tony, I'm very grateful for your help.