# A glimpse at automated AFMA from Nikon



## ahsanford (Apr 21, 2016)

Now showing on the D5 and D500, a feature we might like:

http://www.dpreview.com/news/3468248279/nikons-automated-af-fine-tune-explained

...but the implementation seems very crude and simple. Play the video in the link. Yes, it's better than having to futz around with an incrementally marked target setup, but it appears to only work at one focus distance.

Here's hoping that Canon can do better. 

- A


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## d (Apr 21, 2016)

Wouldn't be too difficult to better. I'm surprised there isn't the option for the camera to automatically repeat the process several times and then take the average value.

Multiple distances is a must, likewise multiple focal lengths for zooms. And since we're going to the trouble, can we also make specific calibration values for outer AF points as well, please?

d.

P.S. His tripod didn't seem particularly stable.


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## neuroanatomist (Apr 21, 2016)

I like the concept. Didn't actually see it in operation, but if it takes a single shot with CDAF and a single shot with PDAF as the basis, I doubt the accuracy and precision. 

Having AFMA'd a whole bunch of lenses, I find many zooms differ across the range – for example, my 24-70/2.8 II is zero at one end and +5 at the other, that's a difference of over half the depth of focus. For me, the ability to calibrate a zoom lens at both ends is important, and trumps automation. But I'd prefer both, of course.


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## Alex_M (Apr 22, 2016)

I used the Live View mode to calibrate my lenses for a while now and I found this method t be very accurate and neat.
I set the target at approx. x50 of the lens focal length to the camera on a steady tripod, switch to the Live View mode, half press the shutter button to acquire focus. Take the note of the distance indicator value on the lens. no need to take a photo. Switch to OVF mode (PDAF) and press the shutter button half way again. pay very close attention to the distance indicator readings of your lens as you do.

1. if the distance indicator readings moved towards infinity (even slightly) - your lens has BACK FOCUSED. adjust the AFMA value in camera. rinse and repeat. 

2. if the distance indicator readings moved towards the Minimum Focus Distance (even slightly) - your lens has FRONT FOCUSED. adjust the AFMA value in camera. rinse and repeat.

3. If distance indicator readings has not changed at all, then the camera PDAF system is in agreement with the CDAF system that the subject was already in focus. NO need to adjust AFMA in camera settings. Rinse and repeat 2 times for consistency.

benefit of this method:

1. no need to take photos at all. saves you hundreds of shutter actuation and your valuable time.
2. critical focus image quality evaluation hard to impossible on camera LCD screen, especially outdoors.
3. no computer, LCD screen required.

this method can be used for a quick AF accuracy verification for critical applications.

I found that this method can be used with great success outdoors focusing on any static contrasty subject.


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## kphoto99 (Apr 22, 2016)

Alex_M said:


> I used the Live View mode to calibrate my lenses for a while now and I found this method t be very accurate and neat.
> I set the target at approx. x50 of the lens focal length to the camera on a steady tripod, switch to the Live View mode, half press the shutter button to acquire focus. Take the note of the distance indicator value on the lens. no need to take a photo. Switch to OVF mode (PDAF) and press the shutter button half way again. pay very close attention to the distance indicator readings of your lens as you do.
> 
> 1. if the distance indicator readings moved towards infinity (even slightly) - your lens has BACK FOCUSED. adjust the AFMA value in camera. rinse and repeat.
> ...



Doesn't work with lenses without distance scale (all STM lenses). For a better method google "dot tune".
I have the FoCal software and I have given up using it in favour of the dot tune method.


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## AlanF (Apr 22, 2016)

There are several methods of doing AFMA badly. I suppose the process of "rinse" at least has the advantage of washing the camera but should be done only with weather-sealed lenses.


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## Alex_M (Apr 22, 2016)

Sir, I can confirm that the method I described above is quite accurate as I was able to double and triple check the results on numerous occasions with Reikan FoCal software and also using traditional Canon recommended technique. there is also 3-Target DoF based technique that I use for the most critical AFMA.

quote author=AlanF link=topic=29663.msg592205#msg592205 date=1461302410]
There are several methods of doing AFMA badly. I suppose the process of "rinse" at least has the advantage of washing the camera but should be done only with weather-sealed lenses. 
[/quote]


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## AlanF (Apr 24, 2016)

Alex_M said:


> Sir, I can confirm that the method I described above is quite accurate as I was able to double and triple check the results on numerous occasions with Reikan FoCal software and also using traditional Canon recommended technique. there is also 3-Target DoF based technique that I use for the most critical AFMA.
> 
> quote author=AlanF link=topic=29663.msg592205#msg592205 date=1461302410]
> There are several methods of doing AFMA badly. I suppose the process of "rinse" at least has the advantage of washing the camera but should be done only with weather-sealed lenses.


[/quote]

I don't understand what "rinse" is?


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## rfdesigner (Apr 24, 2016)

kphoto99 said:


> Alex_M said:
> 
> 
> > I used the Live View mode to calibrate my lenses for a while now and I found this method t be very accurate and neat.
> ...



I was aware of the DotTune method prior to getting my 6D.. having got it, it was trivial to do and all my AF issues (well except speed and any randomness and STM being focus by wire) are out the window.

Magic Lantern even has it automated, not that I've tried ML yet. The only difference I did compared to the official DotTune version was I used a successive approximation method to find the end point of the "in focus range", which made the process somewhat quicker.

My Test target was just a black and white test card I printed off and stuck on the wall.


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## ichiru (Apr 24, 2016)

rfdesigner said:


> kphoto99 said:
> 
> 
> > Alex_M said:
> ...



I tried the magic lantern automated dot tune with my 6D with both tungsten lights and natural light (sideways window light) and although I would leave the camera in the same place... I would get significantly different values each time I repeated the process... any ideas? What type of lighting did you use? Any tips are welcome 

At this stage I think taking a Live View mode shot and comparing it with different MFA values back and forth is the best option as described by 'Alex_M'... FoCal is expensive and I don't know that I can even use it with my Sigma lens...


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## rfdesigner (Apr 24, 2016)

ichiru said:


> I tried the magic lantern automated dot tune with my 6D with both tungsten lights and natural light (sideways window light) and although I would leave the camera in the same place... I would get significantly different values each time I repeated the process... any ideas? What type of lighting did you use? Any tips are welcome
> 
> At this stage I think taking a Live View mode shot and comparing it with different MFA values back and forth is the best option as described by 'Alex_M'... FoCal is expensive and I don't know that I can even use it with my Sigma lens...



Well when I did it I was under CFL lighting, but it's 100% indirect lighting, no spots or anything so it's niegh on impossible to find a shadow (no idea if this helped, but that's how it was). I placed the camera on a tripod (I have a big old heavy video one which is great for this) at about the same distance I like to shoot at most for each lens (different distance for each lens)

I AF in liveview on my B&W target (koren 2003 lens test chart) Then turn the lens from AF to MF and turn off liveview, and then check the AF confirmation. I then dither the AF microadjust +/-10 and check again, then +/-5 check again (but not both ways, just one way looking for the edges of AF confirm) +/-2, check again, then +/-1 homing in on the two points where the AF confrim is flickering, rather than being fully on or off.

Any automated system is going to struggle with the flickering and is likely to come up with a different number each time, but it should be similar. The main problem I had was that one lens had one AF end beyond the end of the microadjust range, so I guessed the breadth of the AF range from the other lenses and estimated it's centre point from just one end of the AF microadjust, but it seems to have worked.

I don't know if that's helpful or "too much" but it's what I did, pretty much word for word. The advantage of using something like a Koren lens test chart is you can then pop off a couple of shots before and after and check the resoltion.. but I also checked against a horizonatal tape measure too.


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## Zeidora (Apr 24, 2016)

Thanks for the two alternate option to check AF-lens combos. I bought FocusTune, and found it utterly useless. Complete waste of $200. Will throw it now in the recycling, will not even try to burden anybody else.


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## Refurb7 (Apr 25, 2016)

ichiru said:


> At this stage I think taking a Live View mode shot and comparing it with different MFA values back and forth is the best option as described by 'Alex_M'... FoCal is expensive and I don't know that I can even use it with my Sigma lens...



FoCal works fine with Sigma lenses. I've used it with the 35 and 50 Art lenses and it worked very well.

I hope Canon introduces an automated system like Nikon's.


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## Woody (Apr 25, 2016)

I used the Magic Lantern automated AF cal function on 6D and was happy with the results.

And yes, AF cal under tungsten and natural light give different results.

Will like to have the Magic Lantern function incorporated into the actual Canon firmware. Right now, Magic Lantern only works for older cameras.


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## ichiru (Apr 25, 2016)

Zeidora said:


> Thanks for the two alternate option to check AF-lens combos. I bought FocusTune, and found it utterly useless. Complete waste of $200. Will throw it now in the recycling, will not even try to burden anybody else.



Thanks for the feedback on FocusTune... sorry to hear you wasted your money. Did you try FoCal ?


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## ichiru (Apr 25, 2016)

Well when I did it I was under CFL lighting, but it's 100% indirect lighting, no spots or anything so it's niegh on impossible to find a shadow (no idea if this helped, but that's how it was). I placed the camera on a tripod (I have a big old heavy video one which is great for this) at about the same distance I like to shoot at most for each lens (different distance for each lens)

I AF in liveview on my B&W target (koren 2003 lens test chart) Then turn the lens from AF to MF and turn off liveview, and then check the AF confirmation. I then dither the AF microadjust +/-10 and check again, then +/-5 check again (but not both ways, just one way looking for the edges of AF confirm) +/-2, check again, then +/-1 homing in on the two points where the AF confrim is flickering, rather than being fully on or off.

Any automated system is going to struggle with the flickering and is likely to come up with a different number each time, but it should be similar. The main problem I had was that one lens had one AF end beyond the end of the microadjust range, so I guessed the breadth of the AF range from the other lenses and estimated it's centre point from just one end of the AF microadjust, but it seems to have worked.

I don't know if that's helpful or "too much" but it's what I did, pretty much word for word. The advantage of using something like a Koren lens test chart is you can then pop off a couple of shots before and after and check the resoltion.. but I also checked against a horizonatal tape measure too.
[/quote]

Thanks for sharing your experience. I do the focus tune with Magic Lantern I figure it's even more 'precise' as I don't move the camera changing settings... it's all automatic. I knew it wasn't working simply because each time I was redoing it, it was giving me a different value! Lmao. 

I'll try it again today. I'll go grab some CFL I guess 5500 K would be best? My printed focusing chart my be crappy too... apparently laser ink has some reflection and as such I'll try inkjet. How would you suggest going about 'indirect light'? bouching off an umbrella would be less harsh but still direct...

Thanks again!


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## ichiru (Apr 25, 2016)

FoCal works fine with Sigma lenses. I've used it with the 35 and 50 Art lenses and it worked very well.

I hope Canon introduces an automated system like Nikon's. 
[/quote]

I guess you translate the Canon MFA value unto the Sigma dock by multiplying by 2?


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## rfdesigner (Apr 25, 2016)

Well when I did it I was under CFL lighting, but it's 100% indirect lighting, no spots or anything so it's niegh on impossible to find a shadow (no idea if this helped, but that's how it was). I placed the camera on a tripod (I have a big old heavy video one which is great for this) at about the same distance I like to shoot at most for each lens (different distance for each lens)

I AF in liveview on my B&W target (koren 2003 lens test chart) Then turn the lens from AF to MF and turn off liveview, and then check the AF confirmation. I then dither the AF microadjust +/-10 and check again, then +/-5 check again (but not both ways, just one way looking for the edges of AF confirm) +/-2, check again, then +/-1 homing in on the two points where the AF confrim is flickering, rather than being fully on or off.

Any automated system is going to struggle with the flickering and is likely to come up with a different number each time, but it should be similar. The main problem I had was that one lens had one AF end beyond the end of the microadjust range, so I guessed the breadth of the AF range from the other lenses and estimated it's centre point from just one end of the AF microadjust, but it seems to have worked.

I don't know if that's helpful or "too much" but it's what I did, pretty much word for word. The advantage of using something like a Koren lens test chart is you can then pop off a couple of shots before and after and check the resoltion.. but I also checked against a horizonatal tape measure too.



ichiru said:


> Thanks for sharing your experience. I do the focus tune with Magic Lantern I figure it's even more 'precise' as I don't move the camera changing settings... it's all automatic. I knew it wasn't working simply because each time I was redoing it, it was giving me a different value! Lmao.
> 
> I'll try it again today. I'll go grab some CFL I guess 5500 K would be best? My printed focusing chart my be crappy too... apparently laser ink has some reflection and as such I'll try inkjet. How would you suggest going about 'indirect light'? bouching off an umbrella would be less harsh but still direct...
> 
> Thanks again!



If I were going to choose a light source I'd go for DC powered tungsten (halogen), again indirectly lit. I believe CFLs will flicker at 100Hz here or 120Hz state-side (unless they have a high frequency converter, maybe some do and some don't perhaps someone can fill in this blank), they are all spectral, Halogens are much broader emission band, only emitting light due to a hot filament, the flicker is also lower.


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## ichiru (Apr 25, 2016)

If I were going to choose a light source I'd go for DC powered tungsten (halogen), again indirectly lit. I believe CFLs will flicker at 100Hz here or 120Hz state-side (unless they have a high frequency converter, maybe some do and some don't perhaps someone can fill in this blank), they are all spectral, Halogens are much broader emission band, only emitting light due to a hot filament, the flicker is also lower.
[/quote]

Hmmm only issue is I would rather calibrate for daylight colour (5600K) as that is the lighting I'm most likely to focus under... and colour seems to affect autofocus (http://www.reikan.co.uk/focalweb/index.php/2014/01/colour-affect-autofocus/)


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## rfdesigner (Apr 25, 2016)

ichiru said:


> If I were going to choose a light source I'd go for DC powered tungsten (halogen), again indirectly lit. I believe CFLs will flicker at 100Hz here or 120Hz state-side (unless they have a high frequency converter, maybe some do and some don't perhaps someone can fill in this blank), they are all spectral, Halogens are much broader emission band, only emitting light due to a hot filament, the flicker is also lower.



Hmmm only issue is I would rather calibrate for daylight colour (5600K) as that is the lighting I'm most likely to focus under... and colour seems to affect autofocus (http://www.reikan.co.uk/focalweb/index.php/2014/01/colour-affect-autofocus/)


I was just concerned that if you had a flickering light is might throw things off.

How about daylight?.. it's the lightsource most like daylight!


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## Refurb7 (Apr 25, 2016)

ichiru said:


> > FoCal works fine with Sigma lenses. I've used it with the 35 and 50 Art lenses and it worked very well.
> >
> > I hope Canon introduces an automated system like Nikon's.
> 
> ...



I use FoCal with each camera's built-in calibration, with the Sigma lenses attached. This way each lens is tuned to each camera.

I have a Sigma dock, but haven't yet used it, and so far don't feel that I need it. My plan was to do in-camera calibration at 50X the focal length, and then to do dock calibration for near distance and infinity, but the near distance and infinity seem to be OK, so I'm going to leave them alone for now.

FoCal is designed to work with your camera's built-in calibration, so I'm not sure whether or how it relates to using the dock settings. It may work as you suggest, but I don't know.

The thing about the dock is that it's designed for calibration at four distances, three of which are very close, and the fourth is infinity. This is good for getting calibration for a range of distance settings, but it tunes the lens generally, not specifically to each camera. (Of course, not a worry if you always use one camera.)

For in-camera calibration, FoCal recommends a distance of 50X the focal length for lenses under 85mm. Check their page for longer lenses. This is good for general purpose calibration. But if using the dock for calibration, you would use the specific distances in the dock software.


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## ichiru (Apr 25, 2016)

Refurb7 said:


> ichiru said:
> 
> 
> > > FoCal works fine with Sigma lenses. I've used it with the 35 and 50 Art lenses and it worked very well.
> ...



Yeah some people on DPreview suggested multiplying FoCal values by 2... I'll give it a shot when I buy it.  I have yet to wrap my head around spending 200 $ for something I might not have to do at all if I just switch to mirrorless... thanks again!


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## TeT (Apr 26, 2016)

Alex_M said:


> benefit of this method:



thanks for the simple methodology ... I NOW have to blow up images to max to ascertain exact focus when AFMA. I can read a distance scale just fine Will save me mucho effort...


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## neuroanatomist (May 4, 2016)

Reikan had a deeper look at the D500's automated AF Fine Tune, compared to their own FoCal process. 

http://www.reikan.co.uk/focalweb/index.php/2016/04/nikon-d500-automatic-af-fine-tune/


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## Mt Spokane Photography (May 4, 2016)

neuroanatomist said:


> Reikan had a deeper look at the D500's automated AF Fine Tune, compared to their own FoCal process.
> 
> http://www.reikan.co.uk/focalweb/index.php/2016/04/nikon-d500-automatic-af-fine-tune/


I just read the article but found Neuro beat me to posting.

With a laptop or pc attached to the camera using liveview, you can probably obtain the critical autofocus needed to properly fine tune the camera, at one point in the zoom range. Unless Nikon has greatly improved live view in their new camera, its frustrating to wait for the image to update, and since its a low resolution image, even then, getting the best possible focus might be difficult or impossible. I had that trouble with my D300S and then my D800.

If that initial AF is not perfect, the calibration will be off!


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## AlanF (May 4, 2016)

*Nikon Fine Tune - FoCal Perspective*

As expected:

http://www.reikan.co.uk/focalweb/index.php/2016/04/nikon-d500-automatic-af-fine-tune/

"*Summary*

There’s a fair amount of detail in this blog post, so I wanted to give a summary of the initial findings.

On the surface, the D500’s automatic AF Fine Tune system does a fair job of quickly calibrating the autofocus system. In reality, however, the need to manually repeat calibrations to iron out variability in results extends the time taken. The need for absolute perfect focus before calibrating introduces a large amount of variability to the results and the lack of consideration for the overall autofocus system (mechanical, optical and electronic together) leads to suboptimal choices by the camera.

If you want to get your AF Fine Tune in roughly the right area without a computer handy, the D500’s auto AF Fine Tune is great. Otherwise (perhaps not surprisingly) we’d recommend to use FoCal!"


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