July 25, 2014, 12:34:28 AM

Author Topic: New MFA method  (Read 19540 times)

neuroanatomist

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Re: New MFA method
« Reply #60 on: February 15, 2013, 11:41:48 AM »
I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.

Thanks for the update (despite the bad new for DotTuneĀ® fans  ;) ).
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Re: New MFA method
« Reply #60 on: February 15, 2013, 11:41:48 AM »

horshack

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Re: New MFA method
« Reply #61 on: February 15, 2013, 03:48:40 PM »
I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.

Can you elaborate on the difference in target+methodology you're using between DotTune and whatever MFA method you're using for "recalibration"? For DotTune are you tuning to a flat DOF vs a 3-D DOF using the other MFA method?  I'm asking because when DotTune is used against a flat target with no DOF reference (chart on wall), then you're tuning an unknown point within the DOF plane. It could be you're tuning at the very edge of the DOF range but you wouldn't be able to know this from a flat target. The alternative would be to DotTune against a target with a 3-D DOF reference, like a LensAlign target. I'd be appreciative if you could try this and report back the results. Thanks!
« Last Edit: February 15, 2013, 03:50:22 PM by horshack »

AlanF

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Re: New MFA method
« Reply #62 on: February 15, 2013, 04:13:43 PM »
Last night I used a patterned lampshade with a bulb behind it as I can do this at night easily. This afternoon, I printed a black + on white A4 paper and focused on that.  I did the sloping ruler test on both reproducibly.  I have also checked visually using the standard iso chart. 
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comsense

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Re: New MFA method
« Reply #63 on: February 15, 2013, 09:19:36 PM »
I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.

Thanks for the update (despite the bad new for DotTuneĀ® fans  ;) ).
From someone who is not a fan of either of the methods: you know very well that there are plenty who cant get it right with either simple ruler or FoCal.
People from companies are known to spread confusion on the forums. Also, online forums are magnet for people who would go to absurd lengths to justified their biased views. Not long ago there was thread full of posts saying "6D is the best full frame camera made by Canon".
So, instead of taking stand at this point I would just wait and watch and try it myself next time I need AFMA.
« Last Edit: February 15, 2013, 09:25:24 PM by comsense »

AlanF

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Re: New MFA method
« Reply #64 on: February 15, 2013, 11:23:58 PM »
I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.

Can you elaborate on the difference in target+methodology you're using between DotTune and whatever MFA method you're using for "recalibration"? For DotTune are you tuning to a flat DOF vs a 3-D DOF using the other MFA method?  I'm asking because when DotTune is used against a flat target with no DOF reference (chart on wall), then you're tuning an unknown point within the DOF plane. It could be you're tuning at the very edge of the DOF range but you wouldn't be able to know this from a flat target. The alternative would be to DotTune against a target with a 3-D DOF reference, like a LensAlign target. I'd be appreciative if you could try this and report back the results. Thanks!

Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work.  For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target.  It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc. 
« Last Edit: February 16, 2013, 03:08:23 AM by AlanF »
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digital paradise

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Re: New MFA method
« Reply #65 on: February 16, 2013, 09:17:21 AM »
Page 4,  Post #10. There is also a link to an article at DPreview. Some light reading  :D 

http://www.fredmiranda.com/forum/topic/1187247/3#11352268
« Last Edit: February 16, 2013, 09:19:39 AM by digital paradise »

horshack

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Re: New MFA method
« Reply #66 on: February 16, 2013, 10:06:42 PM »
Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work.  For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target.  It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.

The advantage of a LensAlign target is that the flat 2-D surface serving as the AF target is machined to be on the same focus plane position as the "0" on the ruler attached to the target, whereas home-grown solutions may not be able to guarantee this tolerance. The LensAlign target also has a sight reference built into it to assure alignment between the camera and the target.

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Re: New MFA method
« Reply #66 on: February 16, 2013, 10:06:42 PM »

AlanF

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Re: New MFA method
« Reply #67 on: February 17, 2013, 12:41:54 AM »
The "0" of my home grown system is placed in the same plane as the target. The ruler rests at about 30deg at the side of a cardboard box and the target is pasted on the front face.  The line on the ruler that touches the target is the 0 point.  The target is perpendicular to the line of sight from the camera.  What is not working is the dot assist on manual focussing relative to focussing in live view.  Does anyone use manual focussing and the dot assist regularly - the spread of 15-20 units is not impressive? Maybe my mistake has been to use the automatic focussing in live view and not tether to a computer and blow up for manual focussing in live view?
« Last Edit: February 17, 2013, 03:53:02 AM by AlanF »
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Re: New MFA method
« Reply #68 on: February 17, 2013, 12:58:29 PM »
One of the good things about FoCal is that it has a new software method for calculating an accurate focus using live view which uses a focal algorithm instead of either PD or CD built into the camera.  It's very slow but meticulous.

IF you want to make sure the dot method is working best, you can use focal to obtain the perfect focus, switch to MF on the lens then continue with dot method.

Still, it is not accurate in my testing on both the 5DIII and 1DX but at least you can use it to ensure perfect focus prior to any testing.

The "0" of my home grown system is placed in the same plane as the target. The ruler rests at about 30deg at the side of a cardboard box and the target is pasted on the front face.  The line on the ruler that touches the target is the 0 point.  The target is perpendicular to the line of sight from the camera.  What is not working is the dot assist on manual focussing relative to focussing in live view.  Does anyone use manual focussing and the dot assist regularly - the spread of 15-20 units is not impressive? Maybe my mistake has been to use the automatic focussing in live view and not tether to a computer and blow up for manual focussing in live view?

comsense

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Re: New MFA method
« Reply #69 on: February 17, 2013, 01:20:12 PM »
Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work.  For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target.  It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.

The advantage of a LensAlign target is that the flat 2-D surface serving as the AF target is machined to be on the same focus plane position as the "0" on the ruler attached to the target, whereas home-grown solutions may not be able to guarantee this tolerance. The LensAlign target also has a sight reference built into it to assure alignment between the camera and the target.
You have lost a lot of your credibility with your nonsensical argument. You are underestimating the capability of some user to achieve precision (same or better than LensAlign). Even then, why is 0 important? Even if 2D target is aligned to 2; you could look around 2. Finally, how is 0 alignment relevant to AFMA by your method? If you need complex 3-D target you got one irrespective.....
Are you CEO of LensAlign resorting to drastic measures to boost sales?
From easy to use with any target, any distance in field about your method, the fine print is creeping in - You need to buy LensAlign target, just to test the method? If someone has to spend $$'s, FoCal already works well!!!!
« Last Edit: February 17, 2013, 01:31:13 PM by comsense »

horshack

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Re: New MFA method
« Reply #70 on: February 17, 2013, 02:43:09 PM »
Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work.  For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target.  It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.


The advantage of a LensAlign target is that the flat 2-D surface serving as the AF target is machined to be on the same focus plane position as the "0" on the ruler attached to the target, whereas home-grown solutions may not be able to guarantee this tolerance. The LensAlign target also has a sight reference built into it to assure alignment between the camera and the target.

You have lost a lot of your credibility with your nonsensical argument. You are underestimating the capability of some user to achieve precision (same or better than LensAlign). Even then, why is 0 important? Even if 2D target is aligned to 2; you could look around 2. Finally, how is 0 alignment relevant to AFMA by your method? If you need complex 3-D target you got one irrespective.....
Are you CEO of LensAlign resorting to drastic measures to boost sales?
From easy to use with any target, any distance in field about your method, the fine print is creeping in - You need to buy LensAlign target, just to test the method? If someone has to spend $$'s, FoCal already works well!!!!


I suggested a LensAlign target only for those that want to DotTune to a precise point within the DOF range. It's not necessary to the process. I'm not affiliated with either LensAlign or FoCal. Also, as an FYI, LensAlign is coming out with their own software product to compete with FoCal: http://www.tapestalk.com/2012/10/focustune-the-rumors-are-true.html
« Last Edit: February 17, 2013, 02:45:28 PM by horshack »

Jaguar2012

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Re: New MFA method
« Reply #71 on: February 17, 2013, 02:44:41 PM »
I wonder if Focal Method "TurboCal" is using similar technique as "DotTune" to perform MFA prediction in 30 Seconds  with no shutter activation in an automated way.

http://www.reikan.co.uk/focalweb/index.php/2013/02/focal-1-8-release-candidate-available-for-focal-pro-users/



« Last Edit: February 17, 2013, 02:47:21 PM by Jaguar2012 »
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horshack

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Re: New MFA method
« Reply #72 on: February 17, 2013, 02:52:32 PM »
I wonder if Focal Method "TurboCal" is using similar technique as "DotTune" to perform MFA prediction in 30 Seconds  with no shutter activation in an automated way.

http://www.reikan.co.uk/focalweb/index.php/2013/02/focal-1-8-release-candidate-available-for-focal-pro-users/


Thanks for the link! I agree, they might be doing something similar to DotTune, provided the Canon SDK+USB interface provides a way to both change the AF tune value programmatically and also feed the PDAF evaluation information over USB to the computer as well.

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Re: New MFA method
« Reply #72 on: February 17, 2013, 02:52:32 PM »

comsense

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Re: New MFA method
« Reply #73 on: February 17, 2013, 03:08:06 PM »
Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work.  For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target.  It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.


The advantage of a LensAlign target is that the flat 2-D surface serving as the AF target is machined to be on the same focus plane position as the "0" on the ruler attached to the target, whereas home-grown solutions may not be able to guarantee this tolerance. The LensAlign target also has a sight reference built into it to assure alignment between the camera and the target.

You have lost a lot of your credibility with your nonsensical argument. You are underestimating the capability of some user to achieve precision (same or better than LensAlign). Even then, why is 0 important? Even if 2D target is aligned to 2; you could look around 2. Finally, how is 0 alignment relevant to AFMA by your method? If you need complex 3-D target you got one irrespective.....
Are you CEO of LensAlign resorting to drastic measures to boost sales?
From easy to use with any target, any distance in field about your method, the fine print is creeping in - You need to buy LensAlign target, just to test the method? If someone has to spend $$'s, FoCal already works well!!!!


I suggested a LensAlign target only for those that want to DotTune to a precise point within the DOF range. It's not necessary to the process. I'm not affiliated with either LensAlign or FoCal. Also, as an FYI, LensAlign is coming out with their own software product to compete with FoCal: http://www.tapestalk.com/2012/10/focustune-the-rumors-are-true.html

If you don't want ability to focus to a precise point within the DOF, why would you bother to AFMA? I am amateur here with fewer shutter clicks than most but I  have about 10 Canon lenses, mostly primes. And none of them would need AFMA if I did not want that precise a focus. Maybe you are missing something in terms of explanation!!!

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Re: New MFA method
« Reply #74 on: February 17, 2013, 04:29:58 PM »

If you don't want ability to focus to a precise point within the DOF, why would you bother to AFMA? I am amateur here with fewer shutter clicks than most but I  have about 10 Canon lenses, mostly primes. And none of them would need AFMA if I did not want that precise a focus. Maybe you are missing something in terms of explanation!!!

Aren't you asking a group who are discussing how to achieve precise focus why they would want to do this, ...if they didn't want to do this?

Well yeeesss, if you didn't want to focus precisely, then you wouldn't need to adjust your camera/lens combo to focus precisely!

Am I missing something? :o

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Re: New MFA method
« Reply #74 on: February 17, 2013, 04:29:58 PM »