Manual focus point question for 6D

[Squidy]

Hi all,

I've got a weird question I was hoping you could help me with. I'm trying to get some good depth of field shots with some friends. Basically I have it so their left eye (if you're looking at them) is close to being on the second "third" vertical line so their other eye is right at the edge of the screen.

The friend is standing about 3 metres or so away from me whereas the background is 30 or so metres. Now, I switch to manual focus point selection, choose the one to the far right (and move the camera so the red focus dot is directly above their left eye), so I set the aperture to F/2.8 and take the shot.

The problem is, instead of focusing on their eye (which is how I assumed it would work) it still seems to focus on the background so that turns out clear but the friend turns out very blurry. It's still a different type of shooting and has some cool effects etc, but I'm just wondering what I'm doing wrong? I thought if the selection was directly over their eye it would focus on that, or at least their face.

Any ideas?

[conropl]

Can you post the example? That would make it easier to figure out.

Barring that, the problem is usually because:

1. If the lens starts out focused more on the back ground than the subject so the subject is blurry and has no clear defined edges, and the background is close enough to the focus point to grab it; then the camera will be satisfied with the background. That is, the focus routine never goes full stroke to get the near field object in focus because it was satisfied with the back ground. Try manually focusing on the subject and then start auto focus
2. Is the subject inside the minimum focus distance for your lens? If you are inside the range the camera is capable of focusing on, then the camera will search until it can find something that within it's minimum focus distance (the background).
3. If there is something with more contrast and sharp lines close to the point, then it grabs that. Try moving the focus point farther away from the edge of the head and where contrasting lines exist (such as the inside corner of the eye).
4. Try using Live view and move the focus box anywhere you want it, zoom in, and focus. Not ideal, but it works when the points not grabbing.
5. From what I understand, the outside points are not that good on the 6D. Also, the focus information is not taken from a specific point, but is in that area (bigger than a pin point). To increase your accuracy, use the center point to focus and then recompose after focus is achieved. The center point is more accurate on the 6D and I believe it is the only focus point that is cross type... so use it if you have critical focusing issues to overcome.

[DavidEccleston]

That's odd. First, verify that it's using the focus point you think it is. If load your RAW into DPP, it can show you which focus point it actually used... perhaps you're using a mode that's selecting a different point than you're expecting, though I would imagine any mode that auto-select your focus points will also prevent you from selecting them.

[Manofmayo66]

I have the 6D and I generally avoid using the outer focus points, preferring instead to focus and recompose (using the center focus point). I found that the accuracy of the outer points is poor for portraits (and really for most things). If I have more time to set up the shot, I will use live view to get a more in focus shot on the boundaries of the frame.

[Squidy]

Hi all,

First of all, sincerest apologies for taking my time to get back to you, I was incredibly snowed under with work.

I don't have any examples because I deleted them but I'll try to get more.

Yeah, they were about 3 metres away from the lens which has a minimum focus distance of 1.5 metres.

If I was to focus then recompose, how could I make sure their eyes are pinpoint sharp?

[conropl]

...If I was to focus then recompose, how could I make sure their eyes are pinpoint sharp?

I am not sure what you are asking, but put the center focus point on the eye and hold the shutter button half way to focus. Hold the button there until you recompose and then push it the rest of the way to release the shutter. This would maintain the focus on the eye unless the subject moved out of the DOF while you were recomposing.

If they are moving to much, then:

1. Compose the shot
2. put in Live View
3. move the box over the eye
4. push the zoom button twice to get it into 10X magnification
5. Adjust the position of the box over the eye again
6. push the shutter... as soon as it focuses on the eye, the shutter will launch.

Pat

[Scott Stephen]

Yes. The outer focus points on my 6d are not reliable. Especially at wide apertures with narrow DOF. I agree that focus and recompose is the way to go if you are wider open than like f/5.6 or so.

If you are shooting with a super narrow DOF and focus on something particular is critical consider framing the subject loosely, using the center AF point WITHOUT recomposing, and then just cropping in post to de-center your subject.

[neuroanatomist]

If it's truly focusing on the background, pay attention to Pat's point – it sounds like you might not be holding the focus lock. To focus-recompose, you need to keep the shutter button half-pressed as you recompose, or set up back button AF. If you focus, release the shutter button, then press it again, it will refocus on whatever is under the AF point after the recompose.

There's another issue with focus-recompose when using thin DoF (wide aperture, close subject) - it guarantees an OOF shot, based on geometry.

http://visual-vacations.com/Photogra...pose_sucks.htm

That's not your issue here, it leads to just slightly OOF shots (focus on the ears instead of the eyes), but it's something to know about if you focus-recompose.

[Dave Throgmartin]

The outer points do work effectively sometimes, but are not as accurate as the center. If I was taking photos for money I would be cautious with the outer AF points.

Dave

[peety3]

If it's truly focusing on the background, pay attention to Pat's point – it sounds like you might not be holding the focus lock. To focus-recompose, you need to keep the shutter button half-pressed as you recompose, or set up back button AF.

Minor BBF rant about to ensue: there's a third way too - AI Servo for continuous focus, then set up back button MF aka Focus Lock. Instead of changing the shutter button behavior to Metering start only plus shoot, leave it as-is, and change the AF-ON button to AF-OFF. Now you can restart focus by clearing the shutter button full-up and re-half-pressing, shoot by full-pressing, and lock focus by holding in the AF-ON (now AF-OFF) button. Much less need to abuse your thumb unless you're such a focus&recompose shooter that you should be back in ONE-SHOT anyway, no need to constantly grip your camera so you can hold the BBF button all day long (I really have to reposition my hand to BBF, or AF-OFF as the case may be), and your thumb is available to use the joystick to choose focus points while you're still shooting with the trigger finger.