August 30, 2014, 08:16:29 AM

Author Topic: New MFA method  (Read 20262 times)

digital paradise

  • Canon 70D
  • ****
  • Posts: 284
    • View Profile
    • Zenon Char Photography
Re: New MFA method
« Reply #30 on: February 10, 2013, 02:41:33 PM »
DotTune. I like it. I'm going to have to wait several days try this with the suggested outer limit AF confirmation. Baby sitting an 11 week old pup and he is into everything. Always under my feet  :D.   

canon rumors FORUM

Re: New MFA method
« Reply #30 on: February 10, 2013, 02:41:33 PM »

Rienzphotoz

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 3322
  • Peace unto all ye Canon, Nikon & Sony shooters
    • View Profile
Re: New MFA method
« Reply #31 on: February 10, 2013, 04:39:16 PM »
Btw I've decided to put a name to the technique so that everyone has an easy way to refer to it and to make it web searchable as it evolves with any improvements. I'm calling it "DotTune", since the focus confirmation dot is central to the technique. I'm also working on a youtube video to bring it to a wider audience.
Excellent job and a neat name ... what I like about this technique is that it is simple, pretty much anyone can do it without having to break their head. AWESOME! ... keep up the good work!
Canon 5DMK3 70D | Nikon D610 | Sony a7 a6000 | RX100M3 | 16-35/2.8LII | 70-200/2.8LISII | 100/2.8LIS | 100-400LIS | 40/2.8 | 50/1.4 | 85/1.8 | 600EX-RTx2 | ST-E3-RT | 24/3.5 T-S | 10-18/4 OSS 16-50 | 24-70/4OSS | 55/1.8 | 55-210 OSS | 70-200/4 OSS | 28-300VR | HVL-F43M | GoPro Black 3+ & DJI Phantom

wayno

  • EOS M2
  • ****
  • Posts: 228
    • View Profile
Re: New MFA method
« Reply #32 on: February 10, 2013, 07:08:17 PM »
Tried this this morning on two lenses - my 85 1.4 Siggy and my 35L. -1 and +1 respectively, which correlates very closely with what I knew. My ranges of AF cut out for both were in the order of +9 and -9 (or thereabouts) - so a range of about 18. This seems like a pretty logical and effective method to me.

Meh

  • 5D Mark III
  • ******
  • Posts: 699
    • View Profile
Re: New MFA method
« Reply #33 on: February 10, 2013, 07:37:55 PM »
Well, this makes FoCal and LensAlign obsolete... or does it?  Could there still be any advantage to a FoCal type method and, if so, how much better might it be? 

The points made about being able to achieve critical/perfect/best (or whatever you might call it) focus using CD are valid, but I think it's a reasonable assumption that manual focus at 10x live view can get real darn close to perfect focus...  anyone have any experience with that?

But, maybe perfect focus or repeatability don't matter so much... even using a theoretically "perfect" method only gets a theoretically "perfect AMFA setting" at one distance.  If we accept that the AFMA setting can not be perfect anyway for all subject distances and focal lengths (for a zoom lens) and all we are trying to do is identify substantial systematic PD focus error and adjust to get closer to the centre of the focus variability then this method may do the job quite well.

Are we sure the focus confirmation dot in the viewfinder works exactly how we think it does?  Does testing for the range of focus confirmation while in MF mode actually give us the centre of the focus variability when PDAF is functioning normally?

Hmmmm....  I suspect we'll see an official word from FoCal why this method doesn't work so good and we will all read it and collectively say "nice try, bye bye".


caruser

  • Rebel T5i
  • ****
  • Posts: 125
    • View Profile
Re: New MFA method
« Reply #34 on: February 11, 2013, 01:03:27 AM »
Hmmmm....  I suspect we'll see an official word from FoCal why this method doesn't work so good and we will all read it and collectively say "nice try, bye bye".
Sorry to be cynical, but we live in a day and age where people and companies with any kind of commercial interest are known to tell a lot of lies and even defend them in court if it means that they can, well, maximise profit. They might of course really have something, but anything they say will have to be double checked. And although I'll have to do some more tests, as I wrote above, double checking this new method the other day indicated that it was spot on for me.

nolken

  • PowerShot G1 X II
  • ***
  • Posts: 37
    • View Profile
Re: New MFA method
« Reply #35 on: February 11, 2013, 01:43:55 AM »
Sounds like this would be a good Magic Lantern implementation.

celliottuk

  • PowerShot G1 X II
  • ***
  • Posts: 32
    • View Profile
Re: New MFA method
« Reply #36 on: February 11, 2013, 02:13:07 AM »
One advantage of this method is that it will work regardless of operating system. FoCal continues to not work with Windows 8 on 2 out of my 3 cameras

canon rumors FORUM

Re: New MFA method
« Reply #36 on: February 11, 2013, 02:13:07 AM »

wayno

  • EOS M2
  • ****
  • Posts: 228
    • View Profile
Re: New MFA method
« Reply #37 on: February 11, 2013, 03:05:55 AM »
Even accounting for a margin of error of say 1-2 on the AFMA scale, I think this is a perfectly valid approach. I don't believe 1-2 (for example) would be noticeable in real life shooting. Essentially I think this method would satisfy 80-90% of AFMA users, even considering AFMA users are a pretty anal bunch :)

Meh

  • 5D Mark III
  • ******
  • Posts: 699
    • View Profile
Re: New MFA method
« Reply #38 on: February 11, 2013, 09:49:20 AM »
Hmmmm....  I suspect we'll see an official word from FoCal why this method doesn't work so good and we will all read it and collectively say "nice try, bye bye".
Sorry to be cynical, but we live in a day and age where people and companies with any kind of commercial interest are known to tell a lot of lies and even defend them in court if it means that they can, well, maximise profit. They might of course really have something, but anything they say will have to be double checked. And although I'll have to do some more tests, as I wrote above, double checking this new method the other day indicated that it was spot on for me.

That was in fact my point... that Focal will issue a explanation of why this DotTune doesn't work but we will say "nice try" to them.  You hit the nail on the head... in order to protect their business they will come up with a reason even if it isn't quite true or if it overstates the advantage of their method.

ddl

  • PowerShot G1 X II
  • ***
  • Posts: 40
    • View Profile
Re: New MFA method
« Reply #39 on: February 11, 2013, 02:18:40 PM »
Focal has the advantage of doing everything automatically (when it works as I've had the odd crash plus 5D3 is semi-auto) plus providing some data analysis and documentation that you can refer to later.

The question is whether that is of any tangible $ value to you if the end result is the same. I like automation (not having to touch the camera once the test is set up) and documentation so it would probably be worth it for me.

comsense

  • Rebel T5i
  • ****
  • Posts: 106
    • View Profile
Re: New MFA method
« Reply #40 on: February 11, 2013, 02:57:10 PM »
I remember all the posts on CR about light and stability requirements for doing FoCal with slight failure resulting in wrong AFMA. Add software glitches, compatibility issues and hooking up laptop to it. In the end, the fact that it can do AFMA automatically is a very small part of the effort (considering you don't even need laptop/image analysis with other method).

However, its not about justifying the FoCal purchase or vice-versa. I don't see FoCal going out of business right away, although it will be a serious dent in their business. Hey, not so long ago, people were happily buying a piece of plastic and a ruler worth $1.5 for $70-100. Ideally, it would be best for most people if we could hand over our Camera-Lenses to a competent assistant who can do the job for us, if we can afford and/or justify the need.

So, I think the question should be asked in reverse: Does this method allow to get the job done with comparable effort and accuracy for someone who does not want to buy FoCal?
« Last Edit: February 11, 2013, 03:03:51 PM by comsense »

East Wind Photography

  • 5D Mark III
  • ******
  • Posts: 680
  • EWP
    • View Profile
Re: New MFA method
« Reply #41 on: February 12, 2013, 11:45:29 AM »
I just tested on a 5DIII and a 600 F/4L with 1.4xIII extender.  Range was -1 to +17.  DOuble checked both ends of the range.  So AFMA value would have been +8.  Took a series of shots and discovered focus was off.  Manually worked down the AFMA range through a series of shots and determined that AFMA 0 produced the sharpest in focus image of the target.  So in this case the Dot Method did not work as expected.

Some thoughts about the process.

1) Live view and phase detect focus may respond differently to color variations in your target or the type of lighting used.  I was shooting in daylight using a concrete wall with several cracks converging to a point.  Not Black and White target.

2) My LV focus may not have been "accurate" such that the predicted AFMA setting was off from where it should have been.  but off by 8???  That would have been noticeable as 8 = a full DOF.

3) AF detect may operate differently depending on object color, contrast, type of lighting used.

So my point here is that there are additional variables to consider that could affect the results.  We put a lot of trust in the camera to do what it's supposed to do on a consistent basis and in fact it's not as consistent as one might think.  You still need to use common sense when making these kinds of adjustments.


Mehmetski

  • Power Shot G16
  • **
  • Posts: 20
    • View Profile
Re: New MFA method
« Reply #42 on: February 13, 2013, 04:38:39 PM »
I tried this today on the 5d3 with my 50L 1.2 and 16-35II's long end and it gave me very inconsistent results. I did this on a controlled light setup, marked my positions at max distance for both lenses, wide open aperture and aligned the target (from lens-align) parallel to the sensor. I tried this technique 3 times on the same positions with both lenses. I shut down the camera and restarted the test after each try. These are the results:
50mm 1.2
first try -5 to +12
second -9 to +9
third -8 to +16

16-35II on 35mm
first try -9 to 10
second -5 to +14
third -6 to +12

Did I do something wrong?

canon rumors FORUM

Re: New MFA method
« Reply #42 on: February 13, 2013, 04:38:39 PM »

East Wind Photography

  • 5D Mark III
  • ******
  • Posts: 680
  • EWP
    • View Profile
Re: New MFA method
« Reply #43 on: February 13, 2013, 05:15:02 PM »
Nope. As mentioned previously I had the same kinds of error.  So in essence the method is flawed.  Relies on an accurate AF confirm which we all have known for some time is pretty darned useless.

It's a very nice concept and one that someday may be refined enough to actually be built into firmware.  Right now it's even worse than FoCal.

I tried this today on the 5d3 with my 50L 1.2 and 16-35II's long end and it gave me very inconsistent results. I did this on a controlled light setup, marked my positions at max distance for both lenses, wide open aperture and aligned the target (from lens-align) parallel to the sensor. I tried this technique 3 times on the same positions with both lenses. I shut down the camera and restarted the test after each try. These are the results:
50mm 1.2
first try -5 to +12
second -9 to +9
third -8 to +16

16-35II on 35mm
first try -9 to 10
second -5 to +14
third -6 to +12

Did I do something wrong?

horshack

  • PowerShot G1 X II
  • ***
  • Posts: 55
    • View Profile
Re: New MFA method
« Reply #44 on: February 13, 2013, 09:15:26 PM »
Nope. As mentioned previously I had the same kinds of error.  So in essence the method is flawed.  Relies on an accurate AF confirm which we all have known for some time is pretty darned useless.

It's a very nice concept and one that someday may be refined enough to actually be built into firmware.  Right now it's even worse than FoCal.

I tried this today on the 5d3 with my 50L 1.2 and 16-35II's long end and it gave me very inconsistent results. I did this on a controlled light setup, marked my positions at max distance for both lenses, wide open aperture and aligned the target (from lens-align) parallel to the sensor. I tried this technique 3 times on the same positions with both lenses. I shut down the camera and restarted the test after each try. These are the results:
50mm 1.2
first try -5 to +12
second -9 to +9
third -8 to +16

16-35II on 35mm
first try -9 to 10
second -5 to +14
third -6 to +12

Did I do something wrong?

I'm actually surprised at how few people have reported DotTune isn't working for them. Not because I don't have confidence in my method, but because I expected the teething period to last longer as people sorted out the nuances of the viewfinder focus confirmation system, not to mention the percentage of users who report MFA issues using even existing methods. In my original dpreview Nikon thread the success rate was close to 100%, whereas on the Canon FM thread there were quite a few more people with issues. But nearly everyone who had problems later reported back and said the method worked for them once they followed the additional guidance I posted in my follow-up posts on that FM thread.

As for the accuracy and precision of the viewfinder confirmation system, I've actually found it to be extremely accurate on both the Nikon and Canon bodies I tried. But it takes patience, diligence, and some practice work through the nuances of its feedback.

canon rumors FORUM

Re: New MFA method
« Reply #44 on: February 13, 2013, 09:15:26 PM »