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Author Topic: AF, MF, LV or what  (Read 899 times)

ErikKaffehr

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AF, MF, LV or what
« on: September 24, 2014, 03:51:56 pm »

Hi,

I feel that we are having a lot of discussions about the superiority of either focusing methods on unrelated threads.

Here is my take on the issue

Af works for most people. You still need to make optimum use of it, like selecting focusing method and focus sensor. But it is a mature technology doing a decent job.
Personally I would rank focusing methods like this, for accuracy:
  • Manual focus using magnified live view. This technique is good enough so you can see and handle lens aberrations. Focus shift may be a problem.
  • Contrast sensing AF is very close to above
  • Magnified optical focusing on a calibrated system or using a split image
  • Phase detection
  • Well designed optical viewfinder, calibrated
  • I am not a strong believer in peaking


Moving objects is a different category
  • Phase detection is needed for distance estimation
  • Enlarged view is often not possible
  • Motion precompesation is needed
  • Some photographers can achieve amazing accuracy using manual AF on moving subjects. But I think this is a gift, like setting a ball in the corner i tennis. It can be trained, but very few can do it really well. Those who can are famous.
  • Modern cameras are not exactly build for manual focusing
  • I am not a strong believer in peaking

Where we are going from here?
  • Live view based focusing makes a lot of progress. Great advantage of this technique is that it uses the actual image for focusing.
  • Feature detection and subject tracking will be helpful. We have it now, but advances will be seen in the future.
  • I feel there is room for developments in peaking, but it needs to be based on actual pixels and not on a line and pixel skipped image.


Best regards
Erik
« Last Edit: September 24, 2014, 04:12:16 pm by ErikKaffehr »
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Erik Kaffehr
 

deejjjaaaa

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Re: AF, MF, LV or what
« Reply #1 on: September 24, 2014, 04:28:08 pm »

  • Manual focus using magnified live view. This technique is good enough so you can see and handle lens aberrations. Focus shift may be a problem.
  • Contrast sensing AF is very close to above

CDAF with many cameras is actually possible with magnified view (in that magnified view - like E-M1 for example)... so you will achieve a very very precise positioning of AF area[/list]
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melchiorpavone

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Re: AF, MF, LV or what
« Reply #2 on: September 24, 2014, 04:40:51 pm »

Hi,

I feel that we are having a lot of discussions about the superiority of either focusing methods on unrelated threads.

Here is my take on the issue

(snip)
  • Some photographers can achieve amazing accuracy using manual AF on moving subjects. But I think this is a gift, like setting a ball in the corner i tennis. It can be trained, but very few can do it really well. Those who can are famous.

Best regards
Erik

I'm not famous. Interestingly, I am pretty good at tennis too. Both take some physical skill, but this can be acquired over time. I have often thought that anticipation is the key to both.
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ErikKaffehr

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Re: AF, MF, LV or what
« Reply #3 on: September 24, 2014, 04:42:32 pm »

    Hi,

    Yes, that is a feature for sure. I guess that we are going to see many usability improvement in the near future.

    Best regards
    Erik

CDAF with many cameras is actually possible with magnified view (in that magnified view - like E-M1 for example)... so you will achieve a very very precise positioning of AF area[/list]
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deejjjaaaa

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Re: AF, MF, LV or what
« Reply #4 on: September 24, 2014, 05:22:23 pm »

  • I am not a strong believer in peaking

one of the features missing from EVF manual focusing implementation... CDAF in the end has to boil down to a number used by firmware to decide that focus is achieved... in addition to focus peaking it might be useful (as an option) to display that metric (a number, or make it a bar or something) somewhere in EVF (calculated for some preselected area within a frame/within magnified view) to so that you can actually see what CDAF thinks when you cross the peak.
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