Dot-Tune: Autofocus Fine Tuning in under 5 minutes
p.5 #1Dot-Tune: Autofocus Fine Tuning in under 5 minutes
schlotz wrote:
Process as described has the lens set to MF using the half shutter to activate the green AF dot.
Right. Not sure what I was thinking. I've been using MF the entire time.
Process as described has the lens set to MF using the half shutter to activate the green AF dot.
Right. Not sure what I was thinking. I've been using MF the entire time.
Feb 17, 2013 at 10:10 AM
p.5 #2Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
Any delay between the shutter half-press and confirmation dot is an immediate disqualification of confirmation for that tune value. It's when there's no delay that I then suggest you keep holding the shutter for 5 seconds to see if the confirmation dot remains solidly lit. I also suggest additional 5-second half-presses at the same value when you're near either end of the tune range, to better confirm the feedback.
Thanks. That explanation cleared everything up. I ran four tests on the 85/1.8 again: -5 to -11; -6 to -12; +2 to -8; and -3 to -12. I'm tossing the +2 to -8 as an outlier and will average the MA scores for the other three, which were remarkably consistant (-8, -9, -7.5)
RonMJ wrote
2) I did not hold the shutter button for 5 seconds waiting for a confirmation or not. You wrote earlier in this post (page 3, #7, first paragraph of your reply) that if there was a delay then that meant it was likely not a confirmed autofocus value. I would press the shutter and if I did not get a quick focus confirm, then I would use the previous value.Thanks. That explanation cleared everything up. I ran four tests on the 85/1.8 again: -5 to -11; -6 to -12; +2 to -8; and -3 to -12. I'm tossing the +2 to -8 as an outlier and will average the MA scores for the other three, which were remarkably consistant (-8, -9, -7.5)
Feb 17, 2013 at 11:04 AM
p.5 #3Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Very interesting. I will try it the next weekend
Feb 17, 2013 at 11:09 AM
p.5 #4Dot-Tune: Autofocus Fine Tuning in under 5 minutes
I've created a simple AF tune midpoint calculator on my website. Here's the link:
http://testcams.com/DotTune/CalcMidPoint.html
http://testcams.com/DotTune/CalcMidPoint.html
Feb 17, 2013 at 01:11 PM
p.5 #5Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Snapsy,
The newest version of the Reikan Focal Pro calibration software has a new method only available for Canon called Turbo Calibration Test (Plus/Pro). The DotTune results and the Turbo Calibration were very close. The only difference was that the Reikan system is fully automatic.
Chris
The newest version of the Reikan Focal Pro calibration software has a new method only available for Canon called Turbo Calibration Test (Plus/Pro). The DotTune results and the Turbo Calibration were very close. The only difference was that the Reikan system is fully automatic.
Chris
Feb 17, 2013 at 09:38 PM
p.5 #6Dot-Tune: Autofocus Fine Tuning in under 5 minutes
mrfozibear wrote:
Snapsy,
The newest version of the Reikan Focal Pro calibration software has a new method only available for Canon called Turbo Calibration Test (Plus/Pro). The DotTune results and the Turbo Calibration were very close. The only difference was that the Reikan system is fully automatic.
Chris
Thanks Chris. Someone on the canonrumors threaded posted the link as well. It appears they released it just a few days ago. Have you tried the TurboCal? Can you describe the process they have you go through to use it, and what it appears to do? Thanks!
Snapsy,
The newest version of the Reikan Focal Pro calibration software has a new method only available for Canon called Turbo Calibration Test (Plus/Pro). The DotTune results and the Turbo Calibration were very close. The only difference was that the Reikan system is fully automatic.
Chris
Thanks Chris. Someone on the canonrumors threaded posted the link as well. It appears they released it just a few days ago. Have you tried the TurboCal? Can you describe the process they have you go through to use it, and what it appears to do? Thanks!
Feb 17, 2013 at 09:57 PM
p.5 #7Dot-Tune: Autofocus Fine Tuning in under 5 minutes
It's a very simple process. 1) Setup Target, 2) Switch lens to MF, 3) Hit Start. The software does the rest. A series of beeps are heard as the software takes the lens through the process of acquiring focus. The software records several data points, then it predicts the AFMA.
Chris
Chris
Feb 17, 2013 at 11:08 PM
p.5 #8Dot-Tune: Autofocus Fine Tuning in under 5 minutes
mrfozibear wrote:
It's a very simple process. 1) Setup Target, 2) Switch lens to MF, 3) Hit Start. The software does the rest. A series of beeps are heard as the software takes the lens through the process of acquiring focus. The software records several data points, then it predicts the AFMA.
Chris
Are you required to establish the correct focus prior to starting the procedure? Do you see the lens actually acquiring focus as the test progresses, ie. distance scale moving indicating movement of the focus element? Is Live View ever entered during the process? Thanks again...
It's a very simple process. 1) Setup Target, 2) Switch lens to MF, 3) Hit Start. The software does the rest. A series of beeps are heard as the software takes the lens through the process of acquiring focus. The software records several data points, then it predicts the AFMA.
Chris
Are you required to establish the correct focus prior to starting the procedure? Do you see the lens actually acquiring focus as the test progresses, ie. distance scale moving indicating movement of the focus element? Is Live View ever entered during the process? Thanks again...
Feb 17, 2013 at 11:21 PM
p.5 #9Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
ChrisAre you required to establish the correct focus prior to starting the procedure? Do you see the lens actually acquiring focus as the test progresses, ie. distance scale moving indicating movement of the focus element? Is Live View ever entered during the process? Thanks again...
I'm curious how it could be completely automatic if you switch the lens to MF. There's no way for the focus motor to activate, correct?
mrfozibear wrote
It's a very simple process. 1) Setup Target, 2) Switch lens to MF, 3) Hit Start. The software does the rest. A series of beeps are heard as the software takes the lens through the process of acquiring focus. The software records several data points, then it predicts the AFMA.Chris
I'm curious how it could be completely automatic if you switch the lens to MF. There's no way for the focus motor to activate, correct?
Feb 17, 2013 at 11:56 PM
p.5 #10Dot-Tune: Autofocus Fine Tuning in under 5 minutes
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video Link
Edited on Feb 18, 2013 at 05:32 PM · View previous versions
Edited on Feb 18, 2013 at 05:32 PM · View previous versions
Feb 18, 2013 at 01:59 PM
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p.5 #11Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video Link
Needs more volume
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video Link
Needs more volume
Feb 18, 2013 at 02:20 PM
p.5 #12Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Love it. Autofocus fine tuning in under 5 minutes.
The video is 18+
The video is 18+
Feb 18, 2013 at 04:04 PM
p.5 #13Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Psychic1 wrote:
Needs more volume
Done, thanks! New link is " target="_blank" rel="nofollow">here
snapsy wrote
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video Link Done, thanks! New link is " target="_blank" rel="nofollow">here
Feb 18, 2013 at 05:32 PM
p.5 #14Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video Link
In the video, the correct midpoint is -4, not 4.
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video Link
In the video, the correct midpoint is -4, not 4.
Feb 18, 2013 at 05:54 PM
p.5 #15Dot-Tune: Autofocus Fine Tuning in under 5 minutes
RonMJ wrote:
In the video, the correct midpoint is -4, not 4.
Thanks Ron! The video shows -4 but it seems I said "4" instead of "minus 4". Hopefully it'll be clear from the video. I can't believe you caught that - I would have watched it a 100 times and probably failed to notice every time. Thanks again.
snapsy wrote
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video LinkThanks Ron! The video shows -4 but it seems I said "4" instead of "minus 4". Hopefully it'll be clear from the video. I can't believe you caught that - I would have watched it a 100 times and probably failed to notice every time. Thanks again.
Feb 18, 2013 at 06:10 PM
p.5 #16Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
That a lens can be consistently out-of-spec in regards to its mechanical positioning relative to where its directed, and that this condition can only be fixed through manufacturer shimming/adjustment as the 50mm manual you referenced indicates, is actually further support for the notion that AF tune cannot correct for such conditions, and that it wasn't designed to.
Okay, I see where you're coming from. BFCV doesn't have anything to do with mechanical positioning. (It doesn't matter for AF accuracy if there is a mechanical positioning error, since the body will command the lens to move until the AF sensor sees an in-focus subject - accuracy depends on detection, not motion. You can induce a mechanical positioning error by using a short extension tube, and the system will still achieve accurate focus.)
AFAIK shimming only affects where "infinity" focus via the focus ring ends up.
BFCV is a number sent by the lens to the body on request, which tells the body how to align a phase match with optimum focus, just like MA does with a value stored in the body. Check out Doug Kerr's Canon EOS Autofocus - BFCV and micro-adjust (MA) for more info.
Wilba wrote
How do you incorporate BFCV, and the idea of lens calibration in general, into your thinking?Okay, I see where you're coming from. BFCV doesn't have anything to do with mechanical positioning. (It doesn't matter for AF accuracy if there is a mechanical positioning error, since the body will command the lens to move until the AF sensor sees an in-focus subject - accuracy depends on detection, not motion. You can induce a mechanical positioning error by using a short extension tube, and the system will still achieve accurate focus.)
AFAIK shimming only affects where "infinity" focus via the focus ring ends up.
BFCV is a number sent by the lens to the body on request, which tells the body how to align a phase match with optimum focus, just like MA does with a value stored in the body. Check out Doug Kerr's Canon EOS Autofocus - BFCV and micro-adjust (MA) for more info.
Feb 18, 2013 at 09:38 PM
p.5 #17Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
Needs more volume Done, thanks! New link is " target="_blank" rel="nofollow">here
Excellent, Thank you Can you lower the volume of my wife 
Psychic1 wrote
snapsy wrote
I've published a DotTune tutorial on YouTube. " target="_blank" rel="nofollow">Video LinkExcellent, Thank you
Can you lower the volume of my wife Feb 19, 2013 at 04:19 AM
p.5 #18Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
Done, thanks! New link is " target="_blank" rel="nofollow">here
Most excellent!
Done, thanks! New link is " target="_blank" rel="nofollow">here
Most excellent!
Feb 19, 2013 at 06:53 AM
p.5 #19Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Thanks, I "snapsy'd" five lenses this morning!
Feb 19, 2013 at 02:18 PM
p.5 #20Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Wilba wrote:
Okay, I see where you're coming from. BFCV doesn't have anything to do with mechanical positioning. (It doesn't matter for AF accuracy if there is a mechanical positioning error, since the body will command the lens to move until the AF sensor sees an in-focus subject - accuracy depends on detection, not motion. You can induce a mechanical positioning error by using a short extension tube, and the system will still achieve accurate focus.)
AFAIK shimming only affects where "infinity" focus via the focus ring ends up.
BFCV is a number sent by the lens to the body on request, which tells...Show more →
That's a really interesting post, thanks Wilba. So it sounds like the lens has an internal database of offsets which the camera can use to bias the PD sensing mechanism to account for positional-specific lens aberrations that would otherwise produce incorrect PD sensing. I imagine the lens could also use the database to offset mechanical nonlinearities in the AF motor/servo.
Okay, I see where you're coming from. BFCV doesn't have anything to do with mechanical positioning. (It doesn't matter for AF accuracy if there is a mechanical positioning error, since the body will command the lens to move until the AF sensor sees an in-focus subject - accuracy depends on detection, not motion. You can induce a mechanical positioning error by using a short extension tube, and the system will still achieve accurate focus.)
AFAIK shimming only affects where "infinity" focus via the focus ring ends up.
BFCV is a number sent by the lens to the body on request, which tells...Show more →
That's a really interesting post, thanks Wilba. So it sounds like the lens has an internal database of offsets which the camera can use to bias the PD sensing mechanism to account for positional-specific lens aberrations that would otherwise produce incorrect PD sensing. I imagine the lens could also use the database to offset mechanical nonlinearities in the AF motor/servo.
Feb 19, 2013 at 02:57 PM