does AF fine tune actually do anything for anyone?

Joined
Jul 15, 2010
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i just went to play around with AF tine tune and my new 70-200 2.8 today.

just to do a rough and dirty test i took 3 images.

used tripod camera angled down at 45 degrees to metal ruler focused on the 5 inch mark

AF fine tune disabled

200mm @ 5.6

5757239010_bdc67f1beb_b.jpg
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Default 0 value by nextelbuddy, on Flickr


AF fine tune = +20

200mm @ 5.6

5756695003_36ce5fc725_b.jpg
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+20 value by nextelbuddy, on Flickr

AF fine tune = -20

200mm @ 5.6

5757239440_9b8c0078bc_b.jpg
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-20 value by nextelbuddy, on Flickr
imported the raw files into lightroom and synced all 3 files with sharpness at 75 and detail set to 50

zoomed in to 100% to the 5 inch mark and all 3 images look completely identical.


it literally did nothing.


when i first tried this i wanted to for ****s and giggles try 200mm @ 2.8 and took 42 pictures.

started At 0 and did all the way through +20 and then all the way through -20

imported all the images and eveyr single image loked identical.


thas why i changed to f5.6 figuring stopping down would make a much clearer difference and even at extremes +20 and -20 they look the same as the - value image.




i se no back focusing or front focusing and it bothers me that i SHOULD have a back focused image @ +20 and i SHOULD have a front focused image @ -20

what gives??

am i doing something wrong?



edit***


adding more photos.


here are images all @ default 0 values NO AF Tuning.

from these images it appears that i shouldnt need any fine tuning anyways i dont think but it would be nice to know why when i do choose af fine tuning i see no differences.

200mm @ f2.8
5757512202_73f8743095_b.jpg
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200mm @ f2.8 by nextelbuddy, on Flickr


200mm @ f5.6
5756967003_327247ff9b_b.jpg
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200mm @ f5.6 by nextelbuddy, on Flickr

200mm @ f8
5756967163_44d5ddbe99_b.jpg
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200mm @ f8 by nextelbuddy, on Flickr

200mm @ f14
5756967315_1f5921ac7d_b.jpg
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200mm @ f14 by nextelbuddy, on Flickr
 
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Joined
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Can you post some samples of the extremes, i.e. +20, 0 and -20? Did you de-focus and re-focus between each fine tune adjustment? I agree it is odd you saw no difference at all!?
 
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I always take the time to verify the focus accuracy of my lenses especially the prime lenses. Move a little closer to the subject so that you'll have a thinner DOF. Here is a sample of my 85mm f1.4 prime which required a -5 to get a spot on AF.

battery_test.jpg
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Can you post some samples of the extremes, i.e. +20, 0 and -20? Did you de-focus and re-focus between each fine tune adjustment? I agree it is odd you saw no difference at all!?

just added 3 images to my original post to show what i meant.


the FOCAL POINT was the 5 INCH mark and in each of the 3 images the 5 inch mark looks exactly the same and i can not see one slight bit of back or front focusing in the +20 or -20 mark.


doesnt that look strange?


i literally changed the DEFAULT VALUE and not the SAVED VALUE..

was that the right value to change?
 
Joined
Feb 27, 2009
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Payson AZ
I can't see any difference either.

I have read here the fine tune is best for primes. I've played with it and just made myself nuts thinking it's working and second guessing myself.
I was also told the 45 deg is the wrong way of doing it. I don't know.

All my values are now zero.
 

Growltiger

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You have to start with the right testing methodology. Your method of focussing on a surface at 45 degrees is exactly what you must not do - there are many messages around explaining why. Basically it means you start by measuring the wrong thing, the focussing of the camera on a confusing, slanted surface, and not the back/front focus which you are trying to measure. Also why test it at close focus? - this too is not optimal.

You need to start by using a good quality focus target at a good distance. I suggest a brick building on the other side of the street.

Yoiu should be storing the Saved value, which is the value for that lens. I think the default value changes it for all lenses, and you really don't want to do that!
 
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What I learned is that I don't know what the hell I'm doing when it comes to AF fine tuning. I spent a lot of time printing test charts, testing lenses, etc. Weeks later, I was going through images in LR and thought "Why don't these images look sharp?" Turned off the AF fine tune, now everything is back to normal. There's no telling how many images I screwed up following the herd on this one.

On not one single occasion since turning it off have I thought "This image would be great if only I'd turned on AF fine tune." So, I'll leave this stuff to my more experienced brethren. I have absolutely no doubt that this is an important and effective option for people who know what they are doing. I am now equally certain that this is yet another topic about which I do NOT know what I'm doing. Just don't see a need to screw with it anymore. Nikon knows what they are talking about when they caution people about using it.
 
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You have to start with the right testing methodology. Your method of focussing on a surface at 45 degrees is exactly what you must not do - there are many messages around explaining why. Basically it means you start by measuring the wrong thing, the focussing of the camera on a confusing, slanted surface, and not the back/front focus which you are trying to measure. Also why test it at close focus? - this too is not optimal.

You need to start by using a good quality focus target at a good distance. I suggest a brick building on the other side of the street.

Yoiu should be storing the Saved value, which is the value for that lens. I think the default value changes it for all lenses, and you really don't want to do that!



ive seen those arguments already and thats why if you look in my original post i posted up pictures of head on images of batteries that were places in 2 inch intervals across and up and down for DOF testing.

still even head on there is no change in values when changing the AF Fine tune.

i even changed the DEFAUL and SAVED values to - 20 and + 20 and tried again and no change whne i zoom in 100% in NX2 or Lightroom 3.

What I learned is that I don't know what the hell I'm doing when it comes to AF fine tuning. I spent a lot of time printing test charts, testing lenses, etc. Weeks later, I was going through images in LR and thought "Why don't these images look sharp?" Turned off the AF fine tune, now everything is back to normal. There's no telling how many images I screwed up following the herd on this one.

On not one single occasion since turning it off have I thought "This image would be great if only I'd turned on AF fine tune." So, I'll leave this stuff to my more experienced brethren. I have absolutely no doubt that this is an important and effective option for people who know what they are doing. I am now equally certain that this is yet another topic about which I do NOT know what I'm doing. Just don't see a need to screw with it anymore. Nikon knows what they are talking about when they caution people about using it.

im starting to feel the same way.
 
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With my 50 1.8 , I found I had to fine tune for the distance it was to be used for. I ended up using a picket fence diagonally at 12 foot focus as a compromise. Close is screwed up, so is far. When I used a diagonal target at 2 feet, the lens would not even focus to infinity. I replaced it with a 50 1.4 AFG. Lens is better by a mile.

No other lens I own requires any fine tune at all, they all work at any distance using the center focus point and single focus mode. The other lenses and cameras are to numerous to mention, but they all work.

Whenever you use dynamic area,focus tracking, 51 points etc, you are never really sure where the target is. These modes are nice for sports, not so good for what I do, portraits & landscape.

I would suggest you set up a target at 6 to 12 feet, and fine tune to that.
 

Growltiger

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1. How did you focus? You should use just the single middle focus point, using S mode. Is it possible you have the camera set so it isn't refocussing each time? Force it by focussing on something else, then focus on the target, before each shot.

2. Did you try a good flat target at a realistic distance? (e.g. brick wall across the street).
 
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1. How did you focus? You should use just the single middle focus point, using S mode. Is it possible you have the camera set so it isn't refocussing each time? Force it by focussing on something else, then focus on the target, before each shot.

2. Did you try a good flat target at a realistic distance? (e.g. brick wall across the street).

yes i always stiuck my hand in front of the lens to get it to refocus and then i refocused on the subject using single point focusing in AF-S mode.


i will try another target today in broad daylight and see if ther are any different results.
 
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Honestly, I'm really bothered by the AF Fine Tune because it only works on the situation and subject I am shooting. Aligning using a LensAlign Pro, for me, does nothing when I'm shooting people, particularly sports. What I do is AF Fine Tune at the location. For instance if I am in the photo pit on first base side at a baseball stadium, I will take a measurement off of the short stop, look at the ground between myself and subject, and keep track of what AF Fine Tuning makes it look great. Then I will do the same thing on the first baseman and then average out the two because I need to cover both. I've noticed my settings change from day to day, lighting to lighting, and uniform to uniform. For me something like a ruler all the way up to the LensAlign Pro, while a cool gadget in the lab, doesn't work in the field.
 
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AF fine tune works, but it has to done in a controlled fashion. First - the camera has to be mounted on a tripod. The AF sensor has to be focusing on exactly the same geometry every time and there can't be camera shake blurring the image. Second - an appropriate AF target has to be used. The thing to avoid is multiple geometries and not knowing what the AF sensor is focusing on. Text on a curved surface is pointless and so is shooting down a ruler, because there is no way of know what portion of what geometry the AF system focused on. It does not matter if the target is close or far (absolute distance makes no difference to the AF system), or if the target is on an angle - so long as the sensor is focusing on a single horizontal line. (I have no interest in what Len Shepard or the rest of his flat earth society have to say, because they simple don't understand how AF systems work.) Having said that, a resolution target set up perfectly perpendicular to the axis of the lens will give less ambiguous results when reviewing images. It's also much easier to see differences with a shallow DOF. Shallow DOF is achieved with large apertures and the target close to the camera.

When I was tuning for each of my lenses, I would first shoot at 0 then +5 checking the images zoomed in on the camera's LCD flicking between images using the rear control dial. If 5 was better than 0, I would go to +10 and see if thing got better or worse and then adjust from there in smaller steps (it's difficult to see differences in adjustments less than 3 units).

Tuning makes the most difference for fast, primes without built in motors.
 
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my opinion only so please don't kill me for it :biggrin:

I think that AF fine tune is useless for zooms, because it's very possible that you can nail perfect focus at one focal length but not on another - It just adds confusion and complexity. The key is to acquire a zoom that is sharp at all focal lengths from the get go. Where the AF Fine Tuning is helpful, in my experience, is with fast primes.
 
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Mar 24, 2009
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Related to uwa, though not exclusively, a landscape photographer (don't remember who) stressed the importance of finding the sharpest infinity focus of a lens (actually any lens). That would be where to turn it in manual focus, no fine tuning involved.

My fine tuning method is to use a tripod and manual focus with stationary subjects when possible. :)

Needed fine tuning, in my experience, varies with zoom and subject distance so rather than optimize one setting and screwing up everything else I don't bother. I did however test my lenses and some were quite off at some settings using proper lensalign type methodology.

I unfortunately don't know what fine tuning does physically. Knowing that would help understand where it's best applicable and why it isn't a universal fix for all lens settings.
 
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Nov 16, 2009
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for zooms I found it worthless because some lenses would bet out of aligment on one extreme and you can't get it aligned without messing the other end. for primes it was a bit better but in lenses like the 135 f/2, I found that the subject distance also was a factor in the adjustment.

it is an interesting feature but nikon is missing the point. they should provide more than one calibration setting for zooms depending on the FL used, and at least one more setting for distances.
 

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