DotTune: Video Tutorial for AF tuning without photographs

Started Feb 18, 2013 | Discussions
Horshack
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Re: It doesn't work for me
In reply to michaeladawson, Feb 26, 2013

michaeladawson wrote:

So I suppose the first thing to say is that we probably need to be careful of misinterpreting words like "way" and "much". So I'll try and be less subjective in the future.

So was the range I observed "way larger"? I don't know. It was larger. I have no way of determining how much larger. So as we troubleshoot I will try to steer away from subjective terms.

Ok, good. I just wanted to make sure you hadn't already tried to body-default range check yet, or some other method to check the range beyond +/- 20.

So what did I observe? If I achieve critical sharp focus in live view then the green dot is solid throughout the entire -20 to +20 fine tune range. Remember, this is for my chipped MF only lenses that I listed above.

For my 50mm f/1.8D AF lens I can actually do Marianne's offset workaround and come up with a green dot range of something like -18 to +20. Barely workable, but workable. I then can go through your dot tune method and can use find the AF fine tune value by confirming one end of the range. I saw no reduction in the range by using your new findings of keeping the AF selector in AF mode and setting the AF-ON button as you describe (my normal setup anyway).

Ok, let's put aside the MF lenses for now since it's possible they'll tune out of the range due to Nikon's "expanded" VF confirmation for MF.

For the 50mm, can you try tuning using the body-default tune value (described here) and see if that fits within +/- 20?

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Kaj E
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Re: This guidance is not fully reliable
In reply to Leonard Shepherd, Feb 28, 2013

Leonard, you make it sound like it is hard to find a good auto-focusing target  It is not. Most well defined subjects with sufficient contrast make good targets. Letter and text are typically excellent as are well defined contrasty objects in nature.

I have never had any problems finding a sufficient good target for my real life photography, particularly if I can prefocus.

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Humanoid
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Worked great for me!
In reply to Kaj E, Mar 1, 2013

I used it with my 600mm VR lens and my D300.  My D300 is set for AF-On and the corrected value was -5.   The delay was the gotcha and I had to pay close attention for it, as it was very slight.

Thanks for this Snappys it worked like a charm!



Result after using Dot Tune.

Cheers,
Ray

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lovEU
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Re: Read Me: Major discovery for reducing confirmed range
In reply to Horshack, Mar 3, 2013

hi, some random questions / thoughts came into my mind having read this thread:

  • Maybe some more testing should be done regarding Kaj E's objection "Why the middle of the range?"
  • Do you eventually have a chance to discuss your method with some guys from Nikon? I guess it would be interesting to get to know what the ones who are doing AF calibration at service centers think about your method.
  • Did you receive any feedback from Marianne Oelund so far? (not within this tread, obviously)
  • Looking at some other AF related threads it looks like one has to do such calibration for different lighting conditions.

Achtually, your method reminds me a bit of a philosopher's stone but I'm not sure how reliable it really can be.

Forgot to say: thanks for sharing.

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Starred
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to Horshack, Mar 3, 2013

Tried it with a D600 and 50/1.8g lens. I have focuslock for all points between -20 and 20.

What can I conclude from this?

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Horshack
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Re: Read Me: Major discovery for reducing confirmed range
In reply to lovEU, Mar 3, 2013

lovEU wrote:

hi, some random questions / thoughts came into my mind having read this thread:

  • Maybe some more testing should be done regarding Kaj E's objection "Why the middle of the range?"
  • Do you eventually have a chance to discuss your method with some guys from Nikon? I guess it would be interesting to get to know what the ones who are doing AF calibration at service centers think about your method.
  • Did you receive any feedback from Marianne Oelund so far? (not within this tread, obviously)
  • Looking at some other AF related threads it looks like one has to do such calibration for different lighting conditions.

Achtually, your method reminds me a bit of a philosopher's stone but I'm not sure how reliable it really can be.

Forgot to say: thanks for sharing.

The questions about DOF and middle-of-the-range were asked/addressed in the posts above in this thread. Using DotTune on a 2-D target has the same implications as using any other tuning method with a 2-D target. If more DOF precision is desired then a 3-D target like LensAlign is suggested. I suppose one could tune to a 2-D target and then try to guess an off-center midpoint adjustment to alter the DOF balance but the relationship between tune adjustment and DOF may vary by distance/situation.

Nikon doesn't appear to want to talk to any of their customers about anything these days

Marianne participated in the original thread and came up with a nice workaround for the +/- 20 tune range case. I don't know if she's tried DotTune herself.

As for reliability, the best way to gauge is to give it a try. Nearly everyone on the original thread reported good results, with many others telling me that DotTune produced results equal to Focal.

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Horshack
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to Starred, Mar 3, 2013

Starred wrote:

Tried it with a D600 and 50/1.8g lens. I have focuslock for all points between -20 and 20.

What can I conclude from this?

Did you leave both the body and lens in AF mode as noted here. If so, can you try the workaround here and report back your results? Thanks!

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Starred
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to Horshack, Mar 3, 2013

Horshack wrote:

Starred wrote:

Tried it with a D600 and 50/1.8g lens. I have focuslock for all points between -20 and 20.

What can I conclude from this?

Did you leave both the body and lens in AF mode as noted here. If so, can you try the workaround here and report back your results? Thanks!

My bad, made a mistake. Pushed the ael/afl button in stead of halfshutter 

Works like a charm now, thanks

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RedBoat
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to Horshack, Mar 15, 2013
Hi guys,
I just used the Dot Tune method to fine-tune the autofocus on my lens.I thoroughly followed the steps described by the author and it turns out that the border of the focus range only starts at -20 (-19 is the first value where I start seeing a confirmation dot, however flickering).At -20 the dot is still flickering.
I assume that I would need to go even lower (for example, to -22) to get a solid confirmation dot). But the scale ends right here at -20.
Could you please help me to understand what is wrong with my setup and what could be done here to further tune the autofocus.
Does it mean that something is wrong with my lens or with the body? And how I can understand which of them (body or lens) causes the problem?
Or should I call Nikon to have them fix this? If so what exactly I would need to tell them to correctly describe the problem (the body is still under warranty).
Thanks.
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Horshack
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to RedBoat, Mar 15, 2013

Hi,

Did you leave both the body and lens in AF mode during the procedure, as described in the post here?

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RedBoat
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to Horshack, Mar 15, 2013

Horshack wrote:

Hi,

Did you leave both the body and lens in AF mode during the procedure, as described in the post here?

Yes i did

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Horshack
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to RedBoat, Mar 15, 2013

RedBoat wrote:

Horshack wrote:

Hi,

Did you leave both the body and lens in AF mode during the procedure, as described in the post here?

Yes i did

Can you try the workaround here and see if it works for you? Thanks!

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RedBoat
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to Horshack, Mar 15, 2013

Thank you for the workaround idea. I'll try it tomorrow morning.

However, does it in general mean that since I'm out of lens fine-tuning range, I would need to take the camera & lens to the service? Is there a way to understand what specifically doesn't work  - is it the camera or the lens?

P.S. I guess a good option would be to try another lens on my camera. I have other lenses, but all of them are zoom lenses, so I'm not sure how I can use this method to fine-tune them.

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Robin Casady
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Re: DotTune: Video Tutorial for AF tuning without photographs
In reply to RedBoat, Mar 15, 2013

RedBoat wrote:

Thank you for the workaround idea. I'll try it tomorrow morning.

However, does it in general mean that since I'm out of lens fine-tuning range, I would need to take the camera & lens to the service? Is there a way to understand what specifically doesn't work - is it the camera or the lens?

P.S. I guess a good option would be to try another lens on my camera. I have other lenses, but all of them are zoom lenses, so I'm not sure how I can use this method to fine-tune them.

You might want to confirm that your Live View focus was accurate by taking a photo and examining it at 100%.

Did you use AF in Live View, or focus manually? Either way, it is worth confirming that it was accurate.

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Kaj E
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Re: Problem: Focus changes during procedure
In reply to Horshack, Mar 15, 2013

I tired the procedure, but could not get it to work. Results were all over the place.

It turned out that the problem is that the focus point switches as soon as I switch from Live view. I focus with live view switch to normal view and then back to live view without doing any refocusing in between, and find that the focus in live view is not where I placed it. I tried in silent mode because I thought that the mirror slap may have changed the focus (activated the AF-On). But silent mode did not help.

Finally gave up. Placed a book on a table with a ruler next to. Took one shot at default to see if I had back or front focus. Then did two shots at large intervals trying to fork the real value. This gave my advice on where to move next and had the focus nailed after a total of 4 shots. Very accurate and easy.

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Horshack
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Re: Problem: Focus changes during procedure
In reply to Kaj E, Mar 15, 2013

Kaj E wrote:

I tired the procedure, but could not get it to work. Results were all over the place.

It turned out that the problem is that the focus point switches as soon as I switch from Live view. I focus with live view switch to normal view and then back to live view without doing any refocusing in between, and find that the focus in live view is not where I placed it. I tried in silent mode because I thought that the mirror slap may have changed the focus (activated the AF-On). But silent mode did not help.

Hmm, I've never seen this before. You're saying you focused in LV, dropped out of LV, went back into LV and the focus was different, without touching any buttons or the focal ring while you were outside of LV? If so, how much did the focus actually change?

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Robin Casady
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Re: Problem: Focus changes during procedure
In reply to Horshack, Mar 15, 2013

Horshack wrote:

Kaj E wrote:

I tired the procedure, but could not get it to work. Results were all over the place.

It turned out that the problem is that the focus point switches as soon as I switch from Live view. I focus with live view switch to normal view and then back to live view without doing any refocusing in between, and find that the focus in live view is not where I placed it. I tried in silent mode because I thought that the mirror slap may have changed the focus (activated the AF-On). But silent mode did not help.

Hmm, I've never seen this before. You're saying you focused in LV, dropped out of LV, went back into LV and the focus was different, without touching any buttons or the focal ring while you were outside of LV? If so, how much did the focus actually change?

I think he is saying that the PDAF focus point is not where the CDAF focus point was.

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Kaj E
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Re: Problem: Focus changes during procedure
In reply to Horshack, Mar 15, 2013

Horshack wrote:

Kaj E wrote:

I tired the procedure, but could not get it to work. Results were all over the place.

It turned out that the problem is that the focus point switches as soon as I switch from Live view. I focus with live view switch to normal view and then back to live view without doing any refocusing in between, and find that the focus in live view is not where I placed it. I tried in silent mode because I thought that the mirror slap may have changed the focus (activated the AF-On). But silent mode did not help.

Hmm, I've never seen this before. You're saying you focused in LV, dropped out of LV, went back into LV and the focus was different, without touching any buttons or the focal ring while you were outside of LV?

Yes. Automatic live view focusing was not very accurate had to do it manually to get it right. Anyhow when I switched out of and back into Live view I needed to do a new manual  focus in live view. But every time I went out and back into live view it needed readjustment.

If so, how much did the focus actually change?

Hard to say,  just needed manual adjustment again.

Because of this several tries to use the DOT process gave wildly different results.

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Kaj
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Horshack
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Re: Problem: Focus changes during procedure
In reply to Kaj E, Mar 15, 2013

Kaj E wrote:

Yes. Automatic live view focusing was not very accurate had to do it manually to get it right. Anyhow when I switched out of and back into Live view I needed to do a new manual focus in live view. But every time I went out and back into live view it needed readjustment.

The only possibility I can think of is if you had LV AF set to AF-F (full-time servo AF), which will cause LV to require focus when you re-enter it. What camera is this on btw?

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Kaj E
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Re: Problem: Focus changes during procedure
In reply to Horshack, Mar 15, 2013

Horshack wrote:

Kaj E wrote:

Yes. Automatic live view focusing was not very accurate had to do it manually to get it right. Anyhow when I switched out of and back into Live view I needed to do a new manual focus in live view. But every time I went out and back into live view it needed readjustment.

The only possibility I can think of is if you had LV AF set to AF-F (full-time servo AF), which will cause LV to require focus when you re-enter it. What camera is this on btw?

D800.

I am quite sure I had the camera set to AF-S. Can't double check now because the camera and lens is at Nikon Melville despite servicing one and a half weeks ago. By the way what is the default for live view AF-S or AF-F in live view (the manual does not seem to tell).? Nikon reset them to default when they had the camera, I had to do all my own settings once I got it back

Your explanation sound logical for my issue. But I remember checking everything before doing the tests, That does however not mean that it's absolute.

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Kaj
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