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Author Topic: About to start with Focal  (Read 31595 times)

neuroanatomist

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Re: About to start with Focal
« Reply #30 on: July 02, 2013, 10:44:25 AM »
I have noticed that my 5D3 will on many occasions forget to record the AFMA value in the EXIF, so I need to enter it manually in Focal. I still haven't figured out exactly what that triggers it.

Do you use back button AF?  If so, and you're not holding the AF-ON button as you press the shutter, the AFMA is not recorded in the EXIF (nor is the selected AF point).
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Re: About to start with Focal
« Reply #30 on: July 02, 2013, 10:44:25 AM »

kaihp

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Re: About to start with Focal
« Reply #31 on: July 02, 2013, 11:06:49 AM »
I have noticed that my 5D3 will on many occasions forget to record the AFMA value in the EXIF, so I need to enter it manually in Focal. I still haven't figured out exactly what that triggers it.

Do you use back button AF?  If so, and you're not holding the AF-ON button as you press the shutter, the AFMA is not recorded in the EXIF (nor is the selected AF point).

I do use the back button AF, so my problem is probably right there. Pretty stupid firmware decision, if you ask me (OK, I know you didn't).
The guy who did that will be second in line to go up against the wall when the revolution comes, just after the guys who made the DSG engine management SW for my VW Golf 1.4 TSI (that SW is seriously FUBAR).

Thanks, neuro.

neuroanatomist

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Re: About to start with Focal
« Reply #32 on: July 02, 2013, 11:16:25 AM »
I have noticed that my 5D3 will on many occasions forget to record the AFMA value in the EXIF, so I need to enter it manually in Focal. I still haven't figured out exactly what that triggers it.

Do you use back button AF?  If so, and you're not holding the AF-ON button as you press the shutter, the AFMA is not recorded in the EXIF (nor is the selected AF point).

I do use the back button AF, so my problem is probably right there. Pretty stupid firmware decision, if you ask me (OK, I know you didn't).

I sort of think it makes sense.  If you're not pressing AF-ON, the camera isn't actively focusing when the shot is taken - therefore, the details of the focus lock aren't recorded.  If you use the shutter half-press to AF, you're always focusing when you fully press the shutter.  With shutter button-linked AF, if you focus-recompose, the selected AF point is recorded, but it's not over the subject.  With back button AF, the selected AF point isn't shown at all - to me, that's better than having it not on the subject.  (Even better would be if it used the gyros for the dual-axis level to compensate for the movement by adjusting for the backfocus that it causes and is evident with a fast prime - but I'm not holding my breath for that one, even though Hasselblad does it.)
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ahab1372

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Re: About to start with Focal
« Reply #33 on: July 02, 2013, 11:30:51 AM »
I sort of think it makes sense.  If you're not pressing AF-ON, the camera isn't actively focusing when the shot is taken - therefore, the details of the focus lock aren't recorded.  If you use the shutter half-press to AF, you're always focusing when you fully press the shutter.  With shutter button-linked AF, if you focus-recompose, the selected AF point is recorded, but it's not over the subject.  With back button AF, the selected AF point isn't shown at all - to me, that's better than having it not on the subject.  (Even better would be if it used the gyros for the dual-axis level to compensate for the movement by adjusting for the backfocus that it causes and is evident with a fast prime - but I'm not holding my breath for that one, even though Hasselblad does it.)
I thought it still recorded AF points. I was looking at a picture yesterday where I'm sure I recomposed, and I could see the AF points in Aperture.
Maybe it is time depended in a way that it records the AF points if not too much time has passed after you let go of the AF-On button - maybe as long as the metering information is still displayed in the VF?
I will test tonight

gbchriste

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Re: About to start with Focal
« Reply #34 on: July 02, 2013, 11:48:30 AM »
Do you use back button AF?  If so, and you're not holding the AF-ON button as you press the shutter, the AFMA is not recorded in the EXIF (nor is the selected AF point).

Not sure that is 100% accurate.  I BBF all the time and don't hold the AF button down when shooting.  I have my 5D3 zoom function set up to automatically zoom to the 10x level and scroll to the AF'd region of the image.  Works every time so the AF point must be recorded in their file somewhere.

gbchriste

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Re: About to start with Focal
« Reply #35 on: July 02, 2013, 11:54:15 AM »
I did my first run through with FoCal last night.  Lately my 70-200 2.8L has been horribly mushy when shooting at 200mm zoom length.  I typically shoot portraits and when I do a full body shot at full zoom, it looks like vaseline has been smeared on the lens.

So I set up FoCal and ran the test.  My first test was done at about 7 meters distance (my wife was mopping the floor so I couldn't move back any further :)) and got a whopping +19 adjustment for the 200mm end.  Yikes!  But the test report showing the various shots at FoCal took at 0, -20, -10, +10, +20 and then the final +19 clearly showed the +0 target way out of focus and the +19 target clearly in focus.

Once the floor dried, I moved back to just shy of 10 meters so was close the recommended focal length X 50 distance.  This time I got a +16 adjustment.

I didn't bother checking the short end as images I take at that end are always razor sharp.

My question is, what happens now?  Does the AFMA adjustment only apply when I am fully zoomed out to 200mm or will the applied adjustment incrementally move back towards zero on a pro-rata basis as I zoom out from 200 back to 70mm?  Or does it just magically flip from the adjusted value back over to zero at some point on the zoom scale?

neuroanatomist

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Re: About to start with Focal
« Reply #36 on: July 02, 2013, 12:06:25 PM »
I sort of think it makes sense.  If you're not pressing AF-ON, the camera isn't actively focusing when the shot is taken - therefore, the details of the focus lock aren't recorded.  If you use the shutter half-press to AF, you're always focusing when you fully press the shutter.  With shutter button-linked AF, if you focus-recompose, the selected AF point is recorded, but it's not over the subject.  With back button AF, the selected AF point isn't shown at all - to me, that's better than having it not on the subject.  (Even better would be if it used the gyros for the dual-axis level to compensate for the movement by adjusting for the backfocus that it causes and is evident with a fast prime - but I'm not holding my breath for that one, even though Hasselblad does it.)
I thought it still recorded AF points. I was looking at a picture yesterday where I'm sure I recomposed, and I could see the AF points in Aperture.
Maybe it is time depended in a way that it records the AF points if not too much time has passed after you let go of the AF-On button - maybe as long as the metering information is still displayed in the VF?
I will test tonight

I do not think that means what you think it means.   ;)

Here are a couple of examples.  The first was a focus-recompose, starting from the lighthouse.  I can assure you that I didn't put the AF point over open blue sky and then focus...  DPP does not show a selected AF point.

The second looks pretty good, like I have the bird nicely centered in the frame and the AF array is on the bird (although not on the head where it should be.  But then look at the full image before cropping. 

Sorry, but Aperture is just making that sh!t up as it goes along...   ::)
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Re: About to start with Focal
« Reply #36 on: July 02, 2013, 12:06:25 PM »

ahab1372

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Re: About to start with Focal
« Reply #37 on: July 02, 2013, 12:07:11 PM »
I did my first run through with FoCal last night.  Lately my 70-200 2.8L has been horribly mushy when shooting at 200mm zoom length.  I typically shoot portraits and when I do a full body shot at full zoom, it looks like vaseline has been smeared on the lens.

So I set up FoCal and ran the test.  My first test was done at about 7 meters distance (my wife was mopping the floor so I couldn't move back any further :)) and got a whopping +19 adjustment for the 200mm end.  Yikes!  But the test report showing the various shots at FoCal took at 0, -20, -10, +10, +20 and then the final +19 clearly showed the +0 target way out of focus and the +19 target clearly in focus.

Once the floor dried, I moved back to just shy of 10 meters so was close the recommended focal length X 50 distance.  This time I got a +16 adjustment.

I didn't bother checking the short end as images I take at that end are always razor sharp.

My question is, what happens now?  Does the AFMA adjustment only apply when I am fully zoomed out to 200mm or will the applied adjustment incrementally move back towards zero on a pro-rata basis as I zoom out from 200 back to 70mm?  Or does it just magically flip from the adjusted value back over to zero at some point on the zoom scale?
The camera will interpolate between the two. You might want to test some focal lengths in between to see if those AFMA values would fall on the interpolated line between your values for wide and tele. If they are way off, and your lens requires AFMA only at the very long end and not in between, I'd consider having the lens checked and adjusted

neuroanatomist

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Re: About to start with Focal
« Reply #38 on: July 02, 2013, 12:13:21 PM »
My question is, what happens now?  Does the AFMA adjustment only apply when I am fully zoomed out to 200mm or will the applied adjustment incrementally move back towards zero on a pro-rata basis as I zoom out from 200 back to 70mm?  Or does it just magically flip from the adjusted value back over to zero at some point on the zoom scale?

It uses a simple integer linear regression to apply AFMA values at focal lenngths between the two ends.  If you set a T value but no W value, it uses 0 as the W value to calculate the regression.  I tested this with my 1D X and some zoom lenses.  For the plot below, each lens was set to W = -10 and T = +10.



For example, with my 24-70 II, I have 0 at the wide end and +5 at the long end.  Based on the calculated regression, it 35mm, it will apply an AFMA of +1, and at 50mm it will apply +3.  I actually tested the lens (with FoCal) at those focal lengths, and the recommended values were exactly that - +1 and +3, respectively.  If that hadn't been the case, I'd have sent the lens back.

In your case, with an adjustment of +16 required, I'd send the lens to Canon for service.
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ahab1372

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Re: About to start with Focal
« Reply #39 on: July 02, 2013, 12:14:04 PM »
I can assure you that I didn't put the AF point over open blue sky and the focus... 
Why not, I do it all the time?  ::)

The second looks pretty good, like I have the bird nicely centered in the frame and the AF array is on the bird (although not on the head where it should be.  But then look at the full image before cropping. 

Sorry, but Aperture is just making that sh!t up as it goes along...   ::)
lol yes those slim AF points are cool, a special feature of the 1DX?
I never bothered to check against EXIF Data before yesterday. I wonder how the Apple engineers are guessing where the AF points are if there is no data at all.

neuroanatomist

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Re: About to start with Focal
« Reply #40 on: July 02, 2013, 12:17:42 PM »
lol yes those slim AF points are cool, a special feature of the 1DX?
I never bothered to check against EXIF Data before yesterday. I wonder how the Apple engineers are guessing where the AF points are if there is no data at all.

Gotta love those crazy Apple engineers.  Heck, sometimes Aperture even completely redesigns the 1D X's AF array.
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J.R.

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Re: About to start with Focal
« Reply #41 on: July 02, 2013, 12:26:37 PM »
lol yes those slim AF points are cool, a special feature of the 1DX?
I never bothered to check against EXIF Data before yesterday. I wonder how the Apple engineers are guessing where the AF points are if there is no data at all.

Gotta love those crazy Apple engineers.  Heck, sometimes Aperture even completely redesigns the 1D X's AF array.

 ;D
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ahab1372

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Re: About to start with Focal
« Reply #42 on: July 02, 2013, 12:28:45 PM »
lol yes those slim AF points are cool, a special feature of the 1DX?
I never bothered to check against EXIF Data before yesterday. I wonder how the Apple engineers are guessing where the AF points are if there is no data at all.

Gotta love those crazy Apple engineers.  Heck, sometimes Aperture even completely redesigns the 1D X's AF array.
Very creative, I have never seen that. Does it happen with pictures after you process them in DXO and then import into Aperture, or with the RAW files directly imported

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Re: About to start with Focal
« Reply #42 on: July 02, 2013, 12:28:45 PM »

neuroanatomist

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Re: About to start with Focal
« Reply #43 on: July 02, 2013, 12:35:13 PM »
Very creative, I have never seen that. Does it happen with pictures after you process them in DXO and then import into Aperture, or with the RAW files directly imported

Good point - it was on a DxO-processed image.  Actually, that's the only one where I've seen it messed up like that - but I don't use the AF point display in Aperture, normally.
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ahab1372

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Re: About to start with Focal
« Reply #44 on: July 02, 2013, 02:13:31 PM »
Here is what I found in my shots:
  • AFMA values are written into the EXIF data, and DPP does display them in the info window, even if AF-On was not pressed.
  • Selected AF points are written into the image, but DPP does not display them if they were not active. Apple Aperture does highlight the selected AF points in thin red lines. If any of them were active, they are displayed in bold red lines. My assumption was based on my previous experience with a Rebel, where only the selected point could be the active.
  • The garbled AF points Neuro showed us have nothing to do with Apple engineers' creativity - cropping or resizing just messes up the relationship between the unaltered positioning values for the AF point, and the actual - altered - dimensions of the image (screenshot attached)

I think I'm slightly off-topic with points 2 and 3 ...
« Last Edit: July 02, 2013, 02:17:20 PM by ahab1372 »

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Re: About to start with Focal
« Reply #44 on: July 02, 2013, 02:13:31 PM »