Using Back Button Focus - For Birds and Landscapes

[Brownbear]

Hi John,

Thank you for sharing. Insightful, and very helpful.

[Stagecoach]

Hi again Christina,

I have digested your post 14, reviewed earlier ones, done some web research (lots of contradictory stuff), looked at your manual again and will make the following comments.

Hi Grahame,

Yes, we are making progress Thank you for your help.

I can see that when I am in continuous focus mode (high speed release) that when keep the BBF pressed that my camera works to keep focus on a moving subject, and that in this mode when I release my hold on the BBF button it is as though my camera switches to manual focus and holds the focus while I recompose... I can repeat this consistently with birds.

Heron... Center Point focus point and recomposed (as above)

This is very encouraging for your results with AF-C mode and is as I would expect.

I headed out this morning and tried Test 11 (Dave's post - Release Mode - S and AF-S)... Clear sunny morning, no mist or fog, and using a tripod.

Although I was not able to manage all the shots in focus, the majority were in focus when I kept my hold on the BBF button while recomposing. However I did have motion blur in a few images so I suspect that it is my technique while recomposing that needs work and/or it may be that when I release my hold on the BBF button something goes wonky.

This is where I'm still concerned in that there are too many references such as not able to manage all shots in focus, majority, motion blur, suspect and the best 'wonky' It suggests uncertainty of what caused results attained or uncertainty of what results should have been attained when using AF-S mode and BBF procedure with your D7100.

I believe there is one fact that you have to ascertain and that is exactly what happens when your D7100 camera is in AF-S, you press the BBF button to attain focus, remove your finger and then press the shutter release (with regard to focus). Knowing this fact will give you the confidence and the knowledge to diagnose things if they do not turn out right.

So here's something to give you 100% confidence and knowledge of your camera in AF-S & BBF use;

1. In AF-S, single shot, centre focus point selected, camera on tripod, aimed at a target such as below, BBF pressed to attain focus, finger then released from BBF button, shutter then pressed take a similar image as this.



2. And then re-compose so that the centre focus point is over something way in the distance (I simply tilted), and pressing nothing other than the shutter release produce this image.



Note, in the example shown I used f/2.8 to clearly show DOF and if focus locks as the manual implies it should you will get an image where the target has obviously remained spot on focus.

Thank you for confirming that focus should be achieved whether I keep my finger on the BBF or not. This is helpful to know.

I am basing my assumption and confirmation on the content of the D7100 manual page 77 para and others comments. There is of course always the possibility these are wrong but the above test should confirm to you what your camera is doing. What I'm also aware of is that the para on page 77 of the manual does not make any reference as to whether it's applicable to specific focus modes.

I just wish it worked the same as when in continuous High Speed focus with AF-C.

I do not want to confuse things at present, but once YOU have confirmed and know exactly what is/should be happening in AF-S(single servo AF) when trying to use BBF with your camera there are other options that can be explored to achieve what you want with BBF.

Aside...
In the AF-S mode if I release my hold on the BBF button because manual focus is needed (mist/fog) is it true that I can just turn the focusing ring on my lens without setting my lens and my camera to manual focus, without damaging my camera?

For some lenses yes, for others no.

Grahame

[Mike Buckley]

if I release my hold on the BBF button because manual focus is needed (mist/fog) is it true that I can just turn the focusing ring on my lens without setting my lens and my camera to manual focus, without damaging my camera?

To clarify Grahame's response that doing so will be fine with some lenses but not with other lenses: If you feel any drag whatsoever when trying to manually focus, don't do it; doing it in that situation might cause damage.

Please be aware that some lenses are designed so that when you are using auto focus, you can instantly change to manual focus by turning the focusing ring on the lens; there will be no need to switch your camera body and/or lens from auto focus to manual focus. If you are using one of those lenses, doing so will never cause any damage. If you are not using one of those lenses, you risk causing damage. Read the User Manual pertaining to each of your lenses to know which lenses allow you to automatically change to manual focus without changing any other lens or camera settings.

[Polar01]

Decided to give the BBF a try, as of know I have to remember that I have to use my thumb to focus. Other than that not too much of a problem. Found a great video by a Steve Perry (not the singer) on the method and setup of using BBF. Watched it, seemed pretty simple and clear not as confusing as the two threads on it. Give it a watch and a read at:

http://nikonrumors.com/2014/01/25/ho...utofocus.aspx/

Cheers: Allan

[Brownbear]

Thank you Grahame... This is very helpful and truly appreciated.

When you took the 2nd shot it does not appear (from your writings) as though you pressed the BBF to focus again after taking the first image? ie; Single Shot auto focus reads to me as though you can only take one shot after focusing...

I am heading out early tomorrow to catch sunrise. I will review your reply and my manual, and Alan's suggested video before heading out.

Yes, there is something about AF-S (Single servo AF) that is confusing to me. This afternoon I uploaded a bunch of landscapes all in focus, photographed this way. The problem is I can't recall how I did these, ie; release or hold the BBF button.

I will find a fence tomorrow and try the same shot as you as wide open as my lens will allow.

Truly appreciated.

Hi again Christina,

I have digested your post 14, reviewed earlier ones, done some web research (lots of contradictory stuff), looked at your manual again and will make the following comments.



This is very encouraging for your results with AF-C mode and is as I would expect.




This is where I'm still concerned in that there are too many references such as not able to manage all shots in focus, majority, motion blur, suspect and the best 'wonky' It suggests uncertainty of what caused results attained or uncertainty of what results should have been attained when using AF-S mode and BBF procedure with your D7100.

I believe there is one fact that you have to ascertain and that is exactly what happens when your D7100 camera is in AF-S, you press the BBF button to attain focus, remove your finger and then press the shutter release (with regard to focus). Knowing this fact will give you the confidence and the knowledge to diagnose things if they do not turn out right.

So here's something to give you 100% confidence and knowledge of your camera in AF-S & BBF use;

1. In AF-S, single shot, centre focus point selected, camera on tripod, aimed at a target such as below, BBF pressed to attain focus, finger then released from BBF button, shutter then pressed take a similar image as this.



2. And then re-compose so that the centre focus point is over something way in the distance (I simply tilted), and pressing nothing other than the shutter release produce this image.



Note, in the example shown I used f/2.8 to clearly show DOF and if focus locked as the manual implies it should you will get an image where the target has obviously remained spot on focus.




I am basing my assumption and confirmation on the content of the D7100 manual page 77 para and others comments. There is of course always the possibility these are wrong but the above test should confirm to you what your camera is doing. What I'm also aware of is that the para on page 77 of the manual does not make any reference as to whether it's applicable to specific focus modes.



I do not want to confuse things at present, but once YOU have confirmed and know exactly what is/should be happening in AF-S(single servo AF) when trying to use BBF with your camera there are other options that can be explored to achieve what you want with BBF.



For some lenses yes, for others no.

Grahame

[Brownbear]

To clarify Grahame's response that, doing so will be fine with some lenses but not with other lenses. If you feel any drag whatsoever when trying to manually focus, don't do it; doing it in that situation might cause damage.

Hi Mike,

Thank you for clarifying. I only have one lens (300 mm f4) that allows me to use manual focus without changing the settings on my camera and lens to MF... When I was researching BBF I read something that suggested that one could just switch to manual focus when using BBF, and I thought it might be true but I'm glad I checked.

Thank you.

Please be aware that some lenses are designed so that when you are using auto focus, you can instantly change to manual focus by turning the focusing ring on the lens; there will be no need to switch your camera body and/or lens from auto focus to manual focus. If you are using one of those lenses, doing so will never cause any damage. If you are not using one of those lenses, you risk causing damage. Read the User Manual pertaining to each of your lenses to know which lenses allow you to automatically change to manual focus without changing any other lens or camera settings.

[Brownbear]

Thank you Allan.

I will review the video, before I head out tomorrow. Appreciated.

I haven't found it difficult to switch to using my thumb to focus, just remembering which mode I'm in and when to press and release the BBF button.

Decided to give the BBF a try, as of know I have to remember that I have to use my thumb to focus. Other than that not too much of a problem. Found a great video by a Steve Perry (not the singer) on the method and setup of using BBF. Watched it, seemed pretty simple and clear not as confusing as the two threads on it. Give it a watch and a read at:

http://nikonrumors.com/2014/01/25/ho...utofocus.aspx/

Cheers: Allan

[Stagecoach]

Thank you Grahame... This is very helpful and truly appreciated.

When you took the 2nd shot it does not appear (from your writings) as though you pressed the BBF to focus again after taking the first image?

Totally disregard how I took the shots, I'm using a different camera to you which I know the BBF procedure is not the same. (But what I will say is that I was in AF-S mode using BBF BUT it does not necessarily mean you will get the same result)

When taking the second shot you should not press the BBF button again before taking it.

ie; Single Shot auto focus reads to me as though you can only take one shot after focusing...

By 'Single shot' I mean not set to Continous Low or High. E.G. One press of the shutter button produces one shot only, not a burst if your finger was to remain pressing it.

I am heading out early tomorrow to catch sunrise. I will review your reply and my manual, and Alan's suggested video before heading out.

Good luck.

Yes, there is something about AF-S (Single servo AF) that is confusing to me. This afternoon I uploaded a bunch of landscapes all in focus, photographed this way. The problem is I can't recall how I did these, ie; release or hold the BBF button.

I will find a fence tomorrow and try the same shot as you as wide open as my lens will allow.

Truly appreciated.

I'm sure that after doing the suggested test it will be less confusing

Grahame

[ajohnw]

Normally single shot AF refers to camera focuses each time the shutter button is pressed. All BBF does is moves that action to the back button.

The video I watched is essentially the same as the one linked to above - must be in AF-C. I have set my D7000 up like this but didn't bother to see if the BB would also control S-AF. I feel there is little point in it doing so anyway. It controls both modes on my E-M1 and when I wanted normal S-AF off the shutter button this is when I found it most inconvenient. I also found that I wasn't too keen on panning and keeping the BB pressed but could get used to this. I did manage a bird in flight with the E-M1 panning very quickly but I found I needed a much faster shutter speed when I looked at the shot. This is an advantage of BBF. I was in a boat going down a river shooting scenery. I might not have had time to change to C-AF. With BBF as per the video it's always available. That is it's main advantage really especially on cheaper cameras that don't have easy switch type access to user modes and the menu's have to be used.

The video also mentions other situations where it can be useful - reframing scenery in particular.

The D7000 manual isn't clear on how focus lock functions. I'd guess that the 7100 is the same. It reads as if it will remain locked for a long as the button is pressed. BBF would obviously be easier if that is the case. The E-M1 has a mode where the BB activates focus and neither focus or exposure is locked until the shutter button is fully depressed - that's why I tried it. It might be worth looking at what other cameras do with exposure in BBF as I found that exposure lock at a 1/2 button press encouraged me to ram the shutter button down when panning as exposure levels are likely to change in this situation and locking exposure on a 1/2 press when some one is getting ready to take has caused me problems.

In terms of manual focus on Nikon lenses I understand all AF-D lenses either need AF disengaged on the camera or their own manual focus switch used if they have one. If any lens does have a manual focus switch then it has to be used on all lens types.

John
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[Mike Buckley]

The problem is I can't recall how I did these, ie; release or hold the BBF button.

I have the same memory issues. To overcome them, I set up a rigorously precise test procedure and take notes. When I return to my computer, I see the results (the images) and my notes indicate what I did to produce the results.

The other advantage of taking notes is that it is extremely well documented that we tend to remember something we write more than something we see and we remember something we hear least of all.

[Brownbear]

Thank you Grahame, John and Mike...

Grahame... Thank you for clarifying.

Mike it is way too cold to write notes this morning (-2 C not accounting for windchill - Seriously I will be freezing while trying this shot but hopefully no haze) but noted and on the next exercise I will do. This morning I will try to follow a specific order, written down before heading out.

[ajohnw]

Thank you Grahame, John and Mike...

Grahame... Thank you for clarifying.

Mike it is way too cold to write notes this morning (-2 C not accounting for windchill - Seriously I will be freezing while trying this shot but hopefully no haze) but noted and on the next exercise I will do. This morning I will try to follow a specific order, written down before heading out.

I have a feeling this is a bit of a stuff that comes out of bulls baffles brains Christina. I'd forget S-AF for a while and set up BBF as the video shows. Then it's simple - want to focus - press the button focusing where you need to and release- it's then locked until you press it again what ever you do. If you need to continue to focus eg BIF keep it pressed until the shot has been taken. Nothing to remember really only the principle - the BB becomes the only mechanism for using the AF.

The other setting you may need to check is Shutter-Release Button AE-L. Nikon default to OFF on that which means that exposure is only locked on a full shutter button press - this is what you want. Some cameras default this to ON which means that exposure and maybe AF will be locked on a 1/2 press. Assuming the D7100 is the same as the D7000 which it probably is the setting will be in the custom setting /fine tuning section of the manual.

John
-

[Brownbear]

Just to say that I can say with confidence from my trial this morning that for the


Nikon D710 set as follows
AE-L/AF-L button set to AF-ON (Back Button Focus)
Release Mode Dial - S (single)
Focus Mode-AF S

1. Acquire focus - holding the BBF button down - Recompose - All shots in focus.

Note: For the above I think that when I lose focus I just can't take the shot but I'm not 100% sure about this statement as it is something I just noticed this morning.

2. Acquire focus - Release my hold on the BBF button - Recompose - All shots in focus.

Note - All shots in focus if I haven't misplaced my focus point or just missed focus/camera movement/pressed the shutter too hard (Frozen shutter button), etc.

If I recall correctly (for #2) I believe I could see the focus indicator button each time I pressed the shutter for the recomposed shots.

In summary for the Nikon D7100 in AF-S Single shot priority both of the above methods work. I confirmed this with a test fence shot, as per Grahame's example and I will post these later this afternoon.

I've decided that I am going to use #2 because I noticed with #1 that I often lost my hold on the BBF button and this resulted in confusion for me.

Thank you everyone for your help and guidance. Very much appreciated!

PS John

Indeed the new finger coordination baffled my brain! I truly appreciate the suggestion but for me it is best to be confident in the results of the method I'm using (different for birds in flight and landscapes), otherwise I have to think about which button to press when - whenever I'm photographing a scene - throws me off kilter - and I'd likely end up permanent baffled.

[Stagecoach]

Hi Christina,

ABSOLUTELY FANTASTIC !!!!!!!

I say this because you had a situation with your camera which you clearly identified was causing you confusion. You have persevered to learn and identify what happens in that specific scenario.

Grahame

[Donald]

Well done, Christina. Part of the joy of photography (of everything) is learning and it's great when you see someone taking one of those significant learning steps forward.

[Mike Buckley]

You have persevered to learn and identify what happens in that specific scenario.

Ditto!

[mknittle]

Good job Christina, Some things take a little confusion to learn. With that now behind you, On the next challenge.

Think of it this way. If it were too easy what fun would it be? I think the challenge is a lot of the attraction of photography.
otherwise we would all buy a point and shoot and call it good.

[Dave Humphries]

Oh dear, it seems I am too late to the party

FWIW at this late stage, I agree with John (ajohnw), there is no point in using AF-S with BBF, in fact I would positively discourage it for wildlife shooting. YMMV
Yes, I tested it, but I did add, in the final paragraph; "Some of the combinations of settings and operation above do not make sense for real world use."

If you want "pseudo AF-S" (to focus and recompose); with the camera in AF-C mode; simply pressing and releasing the BBF button is sufficient to lock focus (give it time to focus, of course) - job done.


As has been said by others above, if you're using AF-S, the camera grabs focus as a one-shot process and even with your finger still held on the BBF button, it won't track any small intentional shift of the focus point - so when you lift off BBF nothing changes, it is still focussed where it was originally, so when you take the shot, it may come out soft because you thought you were focussed somewhere else. I believe this explains the initial batch of 'some soft' results we got.

Yes, there is something about AF-S (Single servo AF) that is confusing to me. This afternoon I uploaded a bunch of landscapes all in focus, photographed this way. The problem is I can't recall how I did these, ie; release or hold the BBF button.

My point exactly - it is confusing

As this thread progressed and you did more tests Christina, I suspect that, with the practice, you got to the stage where even the initial focus action was accurate, so from then on all seemed OK regardless whether in AF-S or AF-C.

However, let me say here and now; I believe that the combination of AF-S and BBF is risky and unnecessary.

Always use AF-C with BBF

(or AI-Servo if you're a Canon shooter)

Well, that's how my brain copes best with it, especially for shooting wildlife - bt not everyone does that uses BBF.
Mike points out (below) that he uses the AF-S beep as focus confirmation - I have mine turned off, so never notice a difference

++++++++++++++++++++++++++++++++++++++++++

Aside...
In the AF-S mode if I release my hold on the BBF button because manual focus is needed (mist/fog) is it true that I can just turn the focusing ring on my lens without setting my lens and my camera to manual focus, without damaging my camera?

On the topic of which lenses are safe to adjust focus without thinking, the easier way (to reading the manual) is to read the legend by the switch on the lens barrel.
Most modern Nikon lenses have a two position switch labelled "M" and "M/A" - in other words; "Manual" and "Manual/Auto", in the latter position, these will be safe to twist focus once your finger is lifted off the BBF button.
I suggest if it says "A" (only), you should not grab it and twist focus (without first switching to "M". I cannot speak for non-Nikon manufactured lenses. Reference to each lens' manual should provide the same information.

++++++++++++++++++++++++++++++++++++++++++

Question…
Is it correct to say that BBF would with the release dial set to Continuous Low, work exactly the same as I have outlined above?

Yes; BBF should work in the same way whether CH, CL or even S, etc.

Simply because in this mode my camera is continually working to retain focus and it is simply a matter of low speed or high speed?

Not really; the CH and CL is only changing the maximum speed of shutter firing repetition, it has nothing to do with focus.
Whether the camera is "working to retain focus" depends entirely on whether you have your finger still held on the BBF button AND that you're in AF-C mode.

++++++++++++++++++++++++++++++++++++++++++

I would also like to acknowledge Grahame's contribution to these discussions in finding the paragraph on p77 of the Nikon D7100 manual which does indeed state that the set a1 and a2 (focus vs release) priorities will be disregarded when using AF-ON (BBF). I missed that in the manual, but my later tests did concur this to be accurate (for a D7100).

Theoretically - in AF-C mode - for pure Birds (or planes) in Flight shooting (no perched shots) - normal 'half-press shutter button' AF should give less un-focused shots because (if set to "Focus" priority) the a1 and a2 settings will be honoured. However, it may also result in a lot less shots captured if you let the focus point slip off the subject, some of which might have been good enough. Plus; if you factor in intermittent need to shoot perched birds and the convenience of never worrying whether you're in AF-S or AF-C, (I think) BBF wins out. YMMV

Cheers, Dave

[Brownbear]

Just to say a special thank you to all for helping me figure this out....

With a special thank you to Grahame for staying with me through this, and to Dave for your impeccable attention to detail. And John for always being there with more info, and Andre for reminding me to look for my focus indicator (it came in handy)

Allan... I watched the video and read the article... Actually I've review this one before but it was good for me to review it again to reinforce everything. And I'd recommend it to others to view.

Donald and Mike...

My very own cheerleaders! Truly, thank you - as always.

Mark...

Thank you. Indeed I learned just this morning that I need to learn how to recompose while using a tripod, but will do.

Dave...

Thank you for the extra detail and advice on using AF-S mode. I presumed it would be better to use this for landscapes because I also presumed that in AF-C my camera would keep focusing but I now have a far better understanding of BBF.

Also thank you for advising on lens and being able to switch to manual focus or not, without switching AF off. I can only do this with my 300 mm lens and I absolutely love this feature. I read an article on BBF which was addressing focus and I suppose at the time I figured that in certain modes BBF was just like putting my camera in manual focus and I was hopeful that this would allow me to avoid having to turn off auto focus on my camera and other lens. I'm truly not sure where these ideas of mine come from.

With respect to recomposing landscapes at this point in time I'm not sure if I like it or not, primarily because my skills at doing this need work. This morning I think I forgot to make sure the camera was still after recomposing. Such a small but important detail.

Grahame....

A very special thank you to you.

Here are my fence shots following your exercise... In focus but with motion blur, and processed by hitting auto.

1. AF-S acquire focus with BBF, release hold on BBF button, recompose and press shutter.





2. AF-S Acquire focus with BBF, keep the BBF button pressed and recompose.






Thank you everyone. It is truly special to be able to receive advice and help, and I hope that one day in the future I will be able to reciprocate.

[Stagecoach]

Just to say a special thank you to all for helping me figure this out....

With a special thank you to Grahame for staying with me through this,

Hi Christina,

No need to thank me but I'm very pleased you appreciate the assistance.

As for staying with you throughout this one I did it for a reason and that was due to your initial post of which you very clearly stated "" simply because at this point in time my only goal is to understand how focusing works in BBF. "" and raised questions regarding BBF operation when in AF-S mode.

My objective was simply to assist you in finding the answers to your specific goal, not give opinions, incorrect information that would cause confusion, superfluous non specif information and where there was doubt a solution to enable confirming an answer.

As for the choice of AF-S OR AF-C mode of operation, now that you have the facts of what happens with BBF in AF-S that you sought for your camera you have the knowledge to assist in making informed decisions.

For me, I use nothing but AF-C when using BBF function, not because I'm not confident or find AF-S and BBF does not work perfectly but because I know that exactly what it gives me can also be obtained in AF-C.


Interesting that you mentioned the 'tripod' operation when re-composing, I did consider at one time changing to a ball head because I considered it may help but have now perfected my procedure with the three way head.

P.S. Nice fence, I have to confess I did not undertake even Auto PP on my balcony rail shots

Grahame