October 20, 2014, 06:49:45 AM

Author Topic: Single point auto focus  (Read 13887 times)

Shawn L

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Re: Single point auto focus
« Reply #15 on: January 04, 2013, 11:09:41 AM »
Personally, I move the AF point around as needed.  I have the default points set off center, and I use orientation-linked AF point to speed things up.  The only time I use an automatic selection mode is in AI Servo for face tracking, where I've already manually selected the starting AF point.

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Re: Single point auto focus
« Reply #15 on: January 04, 2013, 11:09:41 AM »

JaxPhotographer

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Re: Single point auto focus
« Reply #16 on: January 04, 2013, 11:29:44 AM »
Quote
Center point and recompose is certainly faster and easier...and if I'm shooting at f/5.6 with a reasonably distant subject, it's fine because the deeper DoF will mask the backfocus. 

But if you're shooting with a fast prime wide open, focus-recompose is a surefire way to get a backfocused shot.  Some relevant reading: Why Focus-Recompose Sucks.

Personally, I move the AF point around as needed.  I have the default points set off center, and I use orientation-linked AF point to speed things up.  The only time I use an automatic selection mode is in AI Servo for face tracking, where I've already manually selected the starting AF point.

Neuro, your link provides a very effective illustration of the error with focus-recompose for shallow DoF situations. Makes me wonder how many photographers think they have a camera-lense problem with back focusing when it is a technique issue.
« Last Edit: January 04, 2013, 11:45:14 AM by JaxPhotographer »
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RustyTheGeek

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Re: Single point auto focus
« Reply #17 on: January 04, 2013, 12:15:58 PM »
We've been down this road before.  It's a personal preference.  Suffice to say that there are two methods (Center + Recompose or Choose AF Pt) outlined in this discussion and both work fine in most cases.  The argument for moving focus points around instead of recomposing with the center point is sound on paper but not very practical in most cases of shooting.  (IMHO)  Nuero's compromise where he starts out with his AF pt off center might save some effort, I'm not sure.  I guess once you get accustomed to moving the points around with the controls it may get easier but in general I don't think it really matters much until you get into the 2" DOF extremes like is mentioned in the linked article.  If I'm on a tripod in a studio, I can take the time to do anything I want including just tweaking the focus manually.

Personally, I have always used the "center and recompose" method when I shoot "in the field" (not on a tripod in a studio).  I naturally keep in mind the DOF I have to work with and compensate when necessary.  To me the "center and recompose" method is a lot simpler than futzing with AF pts all the time and missing the shot.  The shot is what I am concentrating on, not the AF pt position.  Sometimes, center and recompose isn't even fast enough.  And if you change cameras, you have to start over on learning to change the points again.  Ugh.  And many cameras don't have a selectable AF point feature so you're back to center and recompose anyway.
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enice128

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Re: Single point auto focus
« Reply #18 on: January 04, 2013, 12:38:08 PM »
I use center single-point & back button whether in one shot or servo. Isnt the center square supposed to be the sharpest & most sensitive ???? I have the 1D IV.....or are the other 4 points inside the centre circle all the same? i used to use orientation-linked points but was told to try this method so now in confused again! I'm shooting some basketball tonite so if i can get some input here would be great ....thnaks!!!
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bdunbar79

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Re: Single point auto focus
« Reply #19 on: January 04, 2013, 12:41:48 PM »
I use center single-point & back button whether in one shot or servo. Isnt the center square supposed to be the sharpest & most sensitive ???? I have the 1D IV.....or are the other 4 points inside the centre circle all the same? i used to use orientation-linked points but was told to try this method so now in confused again! I'm shooting some basketball tonite so if i can get some input here would be great ....thnaks!!!

Depends.  On the 1DX, the center strip of points, sans the top and bottom points, are dual cross type points, so should theoretically be equally sensitive.  I have not read any literature on the matter, so I could be incorrect.  I cannot remember the points on the 1D4, sorry.
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RustyTheGeek

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Re: Single point auto focus
« Reply #20 on: January 04, 2013, 12:51:06 PM »
This is one of those topics that is purely a personal preference.  Do whatever works for you.

Look at the images you've taken.  Are they in focus?  Are you satisfied and comfortable with your current technique?

Most important:  Are you getting the shot(s)?  If what you are doing now works for you, I definitely wouldn't try to make a change like this on the fly.  Experiment when it doesn't matter, not tonight at a fast paced sports event!
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enice128

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Re: Single point auto focus
« Reply #21 on: January 04, 2013, 01:02:08 PM »
I agree, its only my nephews game so i shoot for 2 reasons....one, to mostly practice for when it really will count one day hopefully & two, to give some nice shots of him & his teammates. it sort of will be on the fly tonite since this will be the very first time upgrading from my recently traded in 7D thus using my 1D Mark IV.  I will most likely go back to my traditional way of shooting but ill have some time to play around with some other methods....thanks again! But i will tell u, i was so hesitant at first w back-button focusing & now its the ONLY way....even for one shot & portrait work!!!
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Re: Single point auto focus
« Reply #21 on: January 04, 2013, 01:02:08 PM »

RustyTheGeek

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Re: Single point auto focus
« Reply #22 on: January 04, 2013, 01:38:17 PM »
IME, the transition to back button focusing is/was very easy and produced big dividends when I decided to do it.  Trying to peg a specific AF point to a moving subject on the fly just seems very difficult to me with marginal benefit.  I have enough trouble simultaneously thinking about exposure, composition, shutter speed/aperture and how to get that cheerleader doing the splits in midair into the shot on a consistent basis.   :o

Please report back and discuss how it goes for you!!
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enice128

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Re: Single point auto focus
« Reply #23 on: January 04, 2013, 01:45:06 PM »
Thanks for your input! I'm gonna either stick with center point or setup orientation-linked for portrait & landscape which both are NOT center. I'll compare my images over the w/e. But i definitely agree with u regarding having enough to worry about, LOL! My prob lately (& not even sure if it is one) but i actually FORGET that my camera has any other mode than M....i used to always shoot on AV or TV & since M i NEVER switch! Maybe ill try this too?
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Re: Single point auto focus
« Reply #23 on: January 04, 2013, 01:45:06 PM »