Auto Focus question

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nikkito

Argentine Photojournalist
Sep 8, 2011
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Zurich, Switzerland.
www.nicolaszonvi.com
Hey there! I've been taking photos with my 5D Mk II for some time now. fact is, I always use the center focus point. And by always I mean always, I'm used to focusing and recomposing. My question is simple: all of you having cameras with complex autofocus systems (1D, 7D, and now 5D Mk III), how do u use autofocus? Zones? Center point? Etc...

I would like to read what you have to say.
To specify a bit, let's talk about portraits ( I cannot imagine myself using something different than the center focus point), concerts, sports and landscapes.

Thanks in advance & take care :)
Nico :)
 
I'm very interested in figuring it out myself :) Just got the 5d3, and like you coming from a 5d2. From the few minutes I've had with it so far (darn you work!!) it's got zomgtonsofautofocuspoints!1!! Seriously, it feels like the entire view finder is covered with them!

I'll have to see how it works, but I imagine I'll either be using all of them, or point + surrounding points as my primary settings.
 
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I had real issues, as did others, when I got my 7D and used the 'all zone' all points (can't remember what it's called). The camera would usually focus on the nearest point in the frame, not necessarily what was lit in the viewfinder. I set it to centre point expansion and it has been faultless since.
The 5d3 may be better... I haven't bought one, yet.
 
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I had the 5DmkIII for the week-end and from what I could see from the AF, for portrait I would still use a single point center focus most of the time, but the cool thing is because the other point (unlike in the 5DmkII( are also very presice and sensitive, you you can still use a single point but pick the one best suiting your shot composition - so bye bye focus and recomposition method. I think this is cool.

For tracking moving objects, then I would use the zone AF method and pick the zone that works with the composition you are looking for...
 
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I'm fond of all methods at times that feel appropriate to me.

When on a tripod and doing portraits, I like to use a single point which I move where appropriate.
Same scenario but more mobile subjects (kids), I use zones and hope a little.

Sports or fast moving subjects, center point only and put it where I want the focus. Zoom out a bit to leave room to crops.

I frequently leave it on all zone coverage when I'm not doing anything else. Not sure why I do that instead of center zone, but I do.
 
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nikkito said:
Hey there! I've been taking photos with my 5D Mk II for some time now. fact is, I always use the center focus point. And by always I mean always, I'm used to focusing and recomposing. My question is simple: all of you having cameras with complex autofocus systems (1D, 7D, and now 5D Mk III), how do u use autofocus? Zones? Center point? Etc...

I would like to read what you have to say.
To specify a bit, let's talk about portraits ( I cannot imagine myself using something different than the center focus point), concerts, sports and landscapes.

Thanks in advance & take care :)
Nico :)

Using the center point and recomposing works when you are at a small aperture because depth of field hides any small focus error.

However, at wide apertures, the depth of field is so thin that recomposing is going to cause you to miss the focus.

The more advanced cameras will let you focus accurately using almost any of the points, so center point no longer the best option.

I've grown so used to only using only the center point on my 5D MK II, that I may never learn to use the outer points. I'm going to try though.
 
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Personally, I think the 5D3 can accurately focus using any of the (cross-type) AF points, but it's not very intelligent about knowing which of the focus points is the most "interesting" to me. For this reason, I'll probably usually use either one focus point, manually selected, or the expanded region of focus points around my manually selected point.

It will probably depend on how tack-sharp I want the shots. If I'm shooting details, I'll probably have one focus point.. maybe even the spot AF mode. If I'm shooting something like people walking around, probably a wider zone of AF points.

I'll probably keep C-3 or Av in either a wide zone AF or all AF points, for the holy-crap moments. I might use all AF points for the reception dancing "Hail Mary" or "Statue of Liberty" overhead shots, too.
 
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On the 1d mk4 I almost always used single point with expansion, with persons where I wanted face sharp, left/right expansion (useless that you couldn't do this in portrait mode btw). But for very fast erratic movement I used single with surrounding points. I also had the sensitivity set to minus 1 if I had a hard time keeping up with the subject and at 0 if able to follow the subject.

I'm sure going to use spot-AF on the 1d X when Canon finally releases them (*sigh*) which should do wonders for portraits with such lenses as the 50 L , 85 L and 135 L with very shallow dof.
 
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I prefer to select a single AF point that's closest to the subject. That's fine on the 7D, but with the poor outer AF points on the 5DII, I often need to focus/recompose which as Mt. Spokane points out, always results in a backfocused shot with a fast prime shot at a wide aperture. In those cases, I often switch to the Eg-S focus screen and manually focus.

With the 1D X, I'd be back to selecting the nearest AF point, which with the AF system in the 5DIII/1D X is going to be fine, both from an accuracy standpoint, and in terms of having an AF point near the rule-of-thirds intersections (something else the 5DII lacks).
 
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It's definitely going to take some practice for me to get used to the nodes and capabilities of the new AF system, was just using my new 5d3 last night (yay!), and there's just so many options.

I found that with all AF points enabled, it would invariably pick something I didn't want (e.g. a tree or pole closer to me) than the subject I was going for. It was on very busy scenes, both down by the beach on the path, on the streets, etc. I'm still not sure if I'm going to use the point + expansion, or point + surround most of the time, and I'll definitely have to get better and faster at changing the selected point.
 
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