AF-C, AF-S, BBAF vs. shutter release button and focusing issues

rubybgold

Active member
Messages
63
Reaction score
15
I shoot wildlife with my D7500, Tamron 100-400, almost always handheld cuz I'm not fast enough to spot and capture the birds in flight or on the move that I often shoot with a tripod or monopod.

In the four years or so that I've had my 7500, I use all manual settings except autofocus, which I used to use on AF-S, single point of focus, lock the focus in on the middle focus point by depressing the shutter release button half-way and either take the shot, hold it down half-way and recompose, or hold it down half-way and track the movement of the shot, trying to keep the moving subject under that locked focus point. I got a reasonable amount of good images, in focus, but felt like I wasn't utilizing half of the camera's capabilities with AF-C. And, given that most of what I shoot in nature is moving, I wanted to utilize AF-C. So... I tried many times with various settings (i.e. small number of focus points, larger number of focus points, single point, dynamic, etc etc), and was simply just not as successful - rarely got good sharp shots. I came here for advice, tried various things, but rarely found the AF-C successful in capturing sharp shots.

Then I switched to BBAF, which, of course requires keeping the focus setting on AF-C, and I switched AF Priority from 'focus' to 'release' per advice from other photographers on the forums here. BBAF seemed like a great idea - best of both worlds without having to manually switch from AF-S to AF-C in the field, etc, but for the seven months or so since I switched over I'm finding that I very rarely get good super crisp shots with anything moving. Even if an image is fairly good, it's still a little soft. I thought perhaps it's cuz of handholding and the shake I introduce, but got same result with monopod and resting on something. So... now that you've all heard my sad story, here are my questions:

1. Is the BB I appropriated (AE/AF-lock) for BBAF simply not as fast or accurate somehow as the shutter release button on the D7500?

2. Can depressing the shutter release half-way to lock a target in focus under the center focus point and moving along with the moving target keep that moving target in focus better than AF-C for some reason?

3. Might Focus priority be better than Release priority despite all advice to the contrary?

4. Since, for whatever reason, I've not been able to get AF-C to work well for me most of the time to capture moving subjects, and despite my reluctance to not make use of half my camera's capability - is it accurate to think that my old method (depressing shutter release half-way and holding it while moving camera to track moving subject) works as well as BBAF with the BB held in while moving the camera? Or, not so much?

Really been bumming me out how lousy most of my images have been lately - I'd like to get back to feeling successful in focusing images a reasonable percentage of the time again!

Thanks in advance for your thoughts/help with this!
 
Not sure if this would help.

I have a D5600 and I use AF-A most of the time. AF-A is the combination of AF-S and AF-C. The D5600 will choose AF-S if the object is stationary and AF-C if the object is moving.

I have the single point AF at the center. I aimed at taking a good sharp license plate number.

I have just taken a few shots of moving cars outside my house. They were all moving at urban speed, about 50 kph.

These probably are not award winning shots, but they are in focus and reasonably sharp. A higher shutter speed probably would give sharper results.

These were taken with my AF-P 70-300

300 mm - this car was moving away from me

300 mm - this car was moving away from me

300 mm - same

300 mm - same

A closer shot at 85 mm - I panned the camera following this one as it moved across in front of me. I clicked when I could see the license plate.

A closer shot at 85 mm - I panned the camera following this one as it moved across in front of me. I clicked when I could see the license plate.
 
Last edited:
1. Is the BB I appropriated (AE/AF-lock) for BBAF simply not as fast or accurate somehow as the shutter release button on the D7500?
What AF-Area mode are you in? Single, Dynamic, 9pt, 21pt.... I use 9pt most of the time. Depends on the subject/scenario
2. Can depressing the shutter release half-way to lock a target in focus under the center focus point and moving along with the moving target keep that moving target in focus better than AF-C for some reason?
As long as you still have the BBAF button depressed...AF-C is still engaged while you track.
3. Might Focus priority be better than Release priority despite all advice to the contrary?
no
 
Hi. Thanks for responses. WPMChan, thanks for your suggestion, but I never use AF-A because I don't want to give over control to my camera, too many variables can make the wrong decision.

Mako2011 the question I was asking in question 2. was when not using BBAF - but, rather, locking the focus on a subject through the method of depressing the shutter release button half-way and then tracking that moving subject by keeping it within the center focus point as it moves while you hold the shutter release button half-way - in single AF Area and AF-S - would that work the same as AF-C? I'm trying to figure out workarounds if, indeed, for some reason AF-S is better/faster/more accurate than AF-C on my camera.
 
I hear you about the frustration. Modern AF systems are better, but also more complex.

It sounds like your settings and approach are good. I use back button focusing with AF-C and either Single point or a small group. AF-C is a two-edged sword. The good is that it constantly refocuses, so as the subject distance changes the focus adjusts automatically. The bad is that if you drift off the subject, it will focus on whatever is behind that focus point. This is a particular problem when the background is busy. For example, a bird against the sky is usually no problem. But when he flies below the horizon AF can get fooled.

I usually prefocus at an approximate distance first. Then I start tracking the subject without refocusing. When I am confident I'm on the subject, then I press and hold the back button to refocus and shoot.
 
Mako2011 the question I was asking in question 2. was when not using BBAF - but, rather, locking the focus on a subject through the method of depressing the shutter release button half-way and then tracking that moving subject by keeping it within the center focus point as it moves while you hold the shutter release button half-way - in single AF Area and AF-S - would that work the same as AF-C?
No...
I'm trying to figure out workarounds if, indeed, for some reason AF-S is better/faster/more accurate than AF-C on my camera.
It may or may not be. AF-Area mode plays a big part as well as what you have set for menu a3 (Focus Tracking with Lock On). Try AF-C with 9pt and a3 set to "off". That's generally the most accurate setting for subjects in motion. But no one setting works best in every scenerio
 
Mako2011 the question I was asking in question 2. was when not using BBAF - but, rather, locking the focus on a subject through the method of depressing the shutter release button half-way and then tracking that moving subject by keeping it within the center focus point as it moves while you hold the shutter release button half-way - in single AF Area and AF-S - would that work the same as AF-C?
No...
I'm trying to figure out workarounds if, indeed, for some reason AF-S is better/faster/more accurate than AF-C on my camera.
It may or may not be. AF-Area mode plays a big part as well as what you have set for menu a3 (Focus Tracking with Lock On). Try AF-C with 9pt and a3 set to "off". That's generally the most accurate setting for subjects in motion. But no one setting works best in every scenerio
Thanks! Great minds think alike - I had just changed my settings to that. Generally, when using BBAF (which means set to AF-C) - I keep the AF Area Mode on Single. If the subject is stationary - great. If not, and I can track it using BBAF AF-C Single, cool. What I think might be worth trying is if I can't track it with Single using BBAF (which, by def means AF-C on) with 9 pt - seeing if that's any better than Single. I do have Focus Tracking with Lock turned to off currently, thanks!
 
Thanks Jeff - for both the empathy and the suggestion. So much of what I shoot is terrible for AF to grab focus - e.g. subject that has similar colors to the brush/grasses, lots of patterns without a strong edge/contrast for AF to grab on to, etc.

My guess is that I'm either not locking on to the moving subject before I start tracking with it, or that the single point of focus I'm set for drifts off the subject as I move with it with my lens fully extended, and thus harder to control. Switching to D9 might help that, might not - but I'm going to try. Plus, your idea about pre-focusing sounds like a good one.
 
Hey Jeff - quick question - my understanding of AF-C D9 is that if the subject moves out of the AF sensor you originally locked on with and under one of the other sensors, that other sensor will pick up the job of continuing to autofocus. Is that accurate? BTW - your Flicker birds are just lovely. :-)
 
I use bbaf in AFC and set to release priority on all my Nikon's - d7200, d500, d750 and d850. I do a lot of sport and sometimes birds. For me there are no better settings.
 
I use bbaf in AFC and set to release priority on all my Nikon's - d7200, d500, d750 and d850. I do a lot of sport and sometimes birds. For me there are no better settings.
Likewise. One of the reasons I prefer my Panasonic FZ300 and FZ1000 II over the Nikon Coolpix cameras that I owned previously is that I'm able to set them up for BBF just as I do with all of my Nikon ILC bodies.
 
Not sure if this would help.

I have a D5600 and I use AF-A most of the time. AF-A is the combination of AF-S and AF-C. The D5600 will choose AF-S if the object is stationary and AF-C if the object is moving.

I have the single point AF at the center. I aimed at taking a good sharp license plate number.

I have just taken a few shots of moving cars outside my house. They were all moving at urban speed, about 50 kph.

These probably are not award winning shots, but they are in focus and reasonably sharp. A higher shutter speed probably would give sharper results.

These were taken with my AF-P 70-300

300 mm - this car was moving away from me

300 mm - this car was moving away from me

300 mm - same

300 mm - same

A closer shot at 85 mm - I panned the camera following this one as it moved across in front of me. I clicked when I could see the license plate.

A closer shot at 85 mm - I panned the camera following this one as it moved across in front of me. I clicked when I could see the license plate.
When you look ay 100% they are not sharp.

--
Mike.
"I say we take off and nuke the entire site from orbit, it's the only way to be sure."
 
With BBF basically you are pressing the rear button continuously for action shots , and half pressing the shutter button to be ready to take the shot, you are using two fingers to perform, a action that only needs one . If you hold the BB and then stab the shutter release, this leads to camera shake, and I have seen people do this.

I simply use the shutter button, use Dynamic AF and continuous focusing and frame rate, and have a very high keeper rate.

BBF is good for focus and recompose where you follow a subject with CAF and releasing the bb when it stops effectively gives you SAF







--
Mike.
"I say we take off and nuke the entire site from orbit, it's the only way to be sure."
 
When you look ay 100% they are not sharp.
The cars were moving at 50 kph and I was panning the camera to follow the cars as well.

Even that, the motion blur was not bad. I can only see some slight blur when looking up close.

1/750 sec would have produced better results. But that was not the purpose of this exercise.

I only want to demonstrate that AF-A works well for moving cars.

The shots are in focus, and they are all single shots.

PS,

My D5600 is not in the same league of your D500 in AF performance.

PPS,

As the camera was following the cars, AF-C never kicked in. These shots were taken with AF-S.
 
Last edited:
When you look ay 100% they are not sharp.
The cars were moving at 50 kph and I was panning the camera to follow the cars as well.

Even that, the motion blur was not bad. I can only see some slight blur when looking up close.

1/750 sec would have produced better results. But that was not the purpose of this exercise.

I only want to demonstrate that AF-A works well for moving cars.
AF-A is not suitable for moving subjects. The camera achieves focus then locks at that focus distance, but the subject is still moving closer or further away as you take the shot. the time taken between achieving focus and you pressing the shutter results in out of focus shots as in your photos.

In all Nikon manuals S-AF is described as for stationary subjects,
The shots are in focus, and they are all single shots.

PS,

My D5600 is not in the same league of your D500 in AF performance.
The car is only moving at 50kph the D5600 AF is quite capable of achieving sharpness at that speed, I have shots with a D70 from 16 years ago that are sharp and Nikons AF is better now.
 
AF-A is not suitable for moving subjects. The camera achieves focus then locks at that focus distance, but the subject is still moving closer or further away as you take the shot.
Unlike AF-S, AF-A does not necessarily lock at any focal distance.

AF-A is combining both AF-S and AF-C in one setting. AF-A is normally in AF-S when the subject is stationary, AF-C will kick in when the subject starts moving.

All the AF-Area Mode settings are available at AF-A, similar to AF-C. The responsiveness of the AF tracking will depend on which AF-Area mode is chosen.

I like AF-A, as it has both AF-S and AF-C available to me at the same time.
the time taken between achieving focus and you pressing the shutter results in out of focus shots as in your photos.
However, irrespective of how the focus is obtained, AF-C or AF-S, the camera will take a bit more than 0.1 sec to acquire focus. That is the time lag. If the subject is moving away from the camera, the subject will most likely still within the DOF.

However, if the subject is approaching the camera, the shot could be out of focus if the subject moves too fast.

50 kph is about 13.9 m per sec. The car in my first two shots would have moved by about 1.4 m away from the camera after focus had been acquired and before the shutter was released. That would be fine, as their license plates were within the DOF, my focal length was 450 mm FF equiv. and f/5.6.

For the third shot of the white car, the car was moving across the camera and would be still very much in the focal plane, when it moved off from the focus point by 1.4 m.
In all Nikon manuals S-AF is described as for stationary subjects,
Yes. AF-A is for both stationary and moving subjects.
The shots are in focus, and they are all single shots.

PS,

My D5600 is not in the same league of your D500 in AF performance.
The car is only moving at 50kph the D5600 AF is quite capable of achieving sharpness at that speed, I have shots with a D70 from 16 years ago that are sharp and Nikons AF is better now.
Agree. I think the AF performance of my D5600 is very good. Much better than the D40x and D5100 that I had.

Obviously, your D500 is much superior, which has the pro grade AF.
 
AF-A is not suitable for moving subjects. The camera achieves focus then locks at that focus distance, but the subject is still moving closer or further away as you take the shot.
Unlike AF-S, AF-A does not necessarily lock at any focal distance.

AF-A is combining both AF-S and AF-C in one setting. AF-A is normally in AF-S when the subject is stationary, AF-C will kick in when the subject starts moving.

All the AF-Area Mode settings are available at AF-A, similar to AF-C. The responsiveness of the AF tracking will depend on which AF-Area mode is chosen.

I like AF-A, as it has both AF-S and AF-C available to me at the same time.
the time taken between achieving focus and you pressing the shutter results in out of focus shots as in your photos.
However, irrespective of how the focus is obtained, AF-C or AF-S, the camera will take a bit more than 0.1 sec to acquire focus. That is the time lag. If the subject is moving away from the camera, the subject will most likely still within the DOF.
When you track the car with AF-C initiated there is no delay in acquiring focus, in continuous focus the Nikon system calculates continuously where the subject will be when the shutter is pressed.
However, if the subject is approaching the camera, the shot could be out of focus if the subject moves too fast.
The camera allows for that with the predictive focusing.
50 kph is about 13.9 m per sec. The car in my first two shots would have moved by about 1.4 m away from the camera after focus had been acquired and before the shutter was released. That would be fine, as their license plates were within the DOF, my focal length was 450 mm FF equiv. and f/5.6.
DOF would be around 1/2m in front or behind at around 20m. Use CAF and you will not need to rely on DOF, you will get accurate focussing. This was taken with a D200 which has a AF system much older than your D5600. Continuous AF, speed around 200kph or greater.


For the third shot of the white car, the car was moving across the camera and would be still very much in the focal plane, when it moved off from the focus point by 1.4 m.
In all Nikon manuals S-AF is described as for stationary subjects,
Yes. AF-A is for both stationary and moving subjects.
The shots are in focus, and they are all single shots.

PS,

My D5600 is not in the same league of your D500 in AF performance.
The car is only moving at 50kph the D5600 AF is quite capable of achieving sharpness at that speed, I have shots with a D70 from 16 years ago that are sharp and Nikons AF is better now.
Agree. I think the AF performance of my D5600 is very good. Much better than the D40x and D5100 that I had.

Obviously, your D500 is much superior, which has the pro grade AF.
Look at the D200 photo, its how you use the AF that counts.

--
Mike.
"I say we take off and nuke the entire site from orbit, it's the only way to be sure."
 
Last edited:
When you track the car with AF-C initiated there is no delay in acquiring focus, in continuous focus the Nikon system calculates continuously where the subject will be when the shutter is pressed.
The 0.1 sec time lag is the PDAF time lag. It is calculated point by point in succession in continuous tracking. That is with the D5600 as tested by DPR, or 0.111 sec to be exact.

Although I understand that the AF-P lens can acquire focus a bit quicker with its step motor.
However, if the subject is approaching the camera, the shot could be out of focus if the subject moves too fast.

The camera allows for that with the predictive focusing.
I understand predictive focusing only "making up for the short time lag that occurs between releasing the shutter and capturing the image." The PDAF time lag is still there, because the AF algorithm takes time to calculate and adjust the lens to the correct focal length when the focus sensor sees the image. It doesn't do it "continuously". It does it in very quick successions following the focal point tracking.

At least, this is what I can see in my D5600. The focus point jumps in steps as it tracks.
DOF would be around 1/2m in front or behind at around 20m. Use CAF and you will not need to rely on DOF, you will get accurate focussing. This was taken with a D200 which has a AF system much older than your D5600. Continuous AF, speed around 200kph or greater.

That is an impressive shot. Was that a single shot or the best of multi-shot at high frame rates?

I always take single shot. I like the challenge of taking the right moment. I haven't taken motor racing at 200 kph, so I don't know how well single shot will work.

I certainly did not have much problem with anything slower.
Look at the D200 photo, its how you use the AF that counts.
That is exactly what AF-A will do. It has both AF-S and AF-C and will switch to the AF mode as appropriate for the movement of the subject.
 
Last edited:
When you track the car with AF-C initiated there is no delay in acquiring focus, in continuous focus the Nikon system calculates continuously where the subject will be when the shutter is pressed.
The 0.1 sec time lag is the PDAF time lag. It is calculated point by point in succession in continuous tracking. That is with the D5600 as tested by DPR, or 0.111 sec to be exact.
I cant find that on their review of the camera which is very basic,
However, if the subject is approaching the camera, the shot could be out of focus if the subject moves too fast.

The camera allows for that with the predictive focusing.
I understand predictive focusing only "making up for the short time lag that occurs between releasing the shutter and capturing the image." The PDAF time lag is still there, because the AF algorithm takes time to calculate the correct focal length when the focus sensor sees the image. It doesn't do it "continuously". It does it in very quick successions following the focal point tracking.

At least, this is what I can see in my D5600. The focus point jumps in steps as it tracks.
Perhaps that is because the camera is using AF-S, I have used many cameras and never seen that using AF-C, You should choose the appropriate AF instead of assuming the camera is doing it correctly. with AF-C the image in the viewfinder smoothly changes focus as the subject moves. I tried AF-S many years ago with disastrous results, the camera kept locking frame rate until confirmation of focus not allowing the shutter to be fired basically stuttering , that quick succession as the focus point jumps is the sensor locking the distance then finding the subject has moved and re setting the focus, your combination of AF-S and AF-C.
DOF would be around 1/2m in front or behind at around 20m. Use CAF and you will not need to rely on DOF, you will get accurate focussing. This was taken with a D200 which has a AF system much older than your D5600. Continuous AF, speed around 200kph or greater.

That is an impressive shot. Was that a single shot or the best of multi-shot at high frame rates?,
The frame rate on the D200 is only 5FPS the same as the D5600. I dont think I would have been able to take more than 1 frame when the car was in frame due to the high speed of the car, at that angle it's either in frame or not.
I always take single shot. I like the challenge of taking the right moment. I haven't taken motor racing at 200 kph, so I don't know how well single shot will work.
This depends on the camera and track position, A short burst of around 3-4 shots ensures that you get the shot. You can be panning very quickly, and on the first shot you could get shutter shake from pressing the shutter to firmly. Generally if the first shot is OK the others will be to. Its a bit like golf continuing the shot after hitting the ball.I have seen shots from people who claim they only need a single shot but often the shot is blurred by poor panning or not in focus. I take those statements with a grain of salt.
I certainly did not have much problem with anything slower.
Look at the D200 photo, its how you use the AF that counts.
That is exactly what AF-A will do. It has both AF-S and AF-C and will switch to the AF mode as appropriate for the movement of the subject.
Only if it is working as it states.



--
Mike.
"I say we take off and nuke the entire site from orbit, it's the only way to be sure."
 
Perhaps that is because the camera is using AF-S,
No. I set it to AF-C just to see how it works. I am pretty sure that your D500 will work a lot better and smoother.
I have used many cameras and never seen that using AF-C, You should choose the appropriate AF instead of assuming the camera is doing it correctly. with AF-C the image in the viewfinder smoothly changes focus as the subject moves. I tried AF-S many years ago with disastrous results, the camera kept locking frame rate until confirmation of focus not allowing the shutter to be fired basically stuttering , that quick succession as the focus point jumps is the sensor locking the distance then finding the subject has moved and re setting the focus, your combination of AF-S and AF-C.
When Nikon said combination, it is in fact either / or. When the subject moves, it switches to AF-C and stays at AF-S if the subject is stationary.

How well the tracking responses will depend on the setting of the AF-Area mode, on the D5600, it will be from single to 39 points, then 3D and then Auto-area. AF-A uses the same as how anyone will set up the AF-C.
This depends on the camera and track position, A short burst of around 3-4 shots ensures that you get the shot. You can be panning very quickly, and on the first shot you could get shutter shake from pressing the shutter to firmly. Generally if the first shot is OK the others will be to. Its a bit like golf continuing the shot after hitting the ball.I have seen shots from people who claim they only need a single shot but often the shot is blurred by poor panning or not in focus. I take those statements with a grain of salt.
Agree. You have a lot of experience in photographing motor racing and fast moving sports.
Only if it is working as it states.
It does. I have been using that all the time. AF-A is the Nikon default AF setting. It is my default AF setting on my D5100 and now D5600.

We had this discussion on this forum before. Many felt that the Camera took away the control from the photographer. But in fact, I actually have more AF mode available to me at my finger tip all the time. I don't need to switch over as the circumstances changes.
 
Last edited:

Keyboard shortcuts

Back
Top