5D MKII AF Point Selection when photographing children

cwoodard

I just got my new 5D MKII with an EF 70-200mm f/2.8L IS II lens today and after going through the manual and playing around with it some, I'm still unsure about autofocus point selection.

I photograph children in a studio setting and outdoors. They don't stay still very well. Previously I was using the center AF point and recomposing. Got a good percentage of out of focus shots.

Did some more googling tonight and now realize that using the center point and recomposing when trying to get a lot of depth of field will result in out of focus shots.

People suggest, as does Canon, to use the focus point closest to where you want to it to focus (i.e. eyes). I know how to switch the focus point, and will definitely attempt to do that more when I have the time, but there often is no time when photographing children. Stop to change the AF point and the shot is long gone.

In the studio I am going to start shooting f/8 - f/11 to try and avoid some of that issue - so in that case will focus/recompose work? This article (http://visual-vacations.com/Photography/focus-recompose_sucks.htm) suggests picking one of the outer focus points if you need to focus/recompose.

What if I am outdoors and want more depth of field to reduce a distracting background? Try an outer AF selection point?

Thanks in advance for any suggestions!

Dan7312

I don't know how it how it works on the 5D II but on the 7D you can configure the joystick/button on the back of the camera so you can move the focus point with your thumb while you are looking through the viewfinder to compose the image. So you might have to rummage through the manual a bit more, but hopefully someone else while chime in the the custom setting.

cwoodard wrote: »

I just got my new 5D MKII with an EF 70-200mm f/2.8L IS II lens today and after going through the manual and playing around with it some, I'm still unsure about autofocus point selection.

I photograph children in a studio setting and outdoors. They don't stay still very well. Previously I was using the center AF point and recomposing. Got a good percentage of out of focus shots.

Did some more googling tonight and now realize that using the center point and recomposing when trying to get a lot of depth of field will result in out of focus shots.

People suggest, as does Canon, to use the focus point closest to where you want to it to focus (i.e. eyes). I know how to switch the focus point, and will definitely attempt to do that more when I have the time, but there often is no time when photographing children. Stop to change the AF point and the shot is long gone.

In the studio I am going to start shooting f/8 - f/11 to try and avoid some of that issue - so in that case will focus/recompose work? This article (http://visual-vacations.com/Photography/focus-recompose_sucks.htm) suggests picking one of the outer focus points if you need to focus/recompose.

What if I am outdoors and want more depth of field to reduce a distracting background? Try an outer AF selection point?

Thanks in advance for any suggestions!

ziggy53

Focus and recompose does not work when you work with large apertures and "narrow" DOF. At small apertures you can have much deeper DOF and it can work, especially if you have lenses that allow you to tweak the focus after setting AF. (Many lenses with "ring ultrasonic*" focus motor technology allow "full-time manual focus" meaning that you can AF and then override manually.)

Choosing a focus point closer to the subject's point of desired focus does work but generally you need to direct a series of images.

Let's say you want to shoot in portrait orientation with a specific action-activity-background. Rotate the camera to portrait, set the AF point that will most likely work for the subject and scene, and direct the action accordingly.

Focus, shoot and recompose through cropping can also work using the center AF dot alone. The 5D MKII has enough resolution and image quality that cropping in post is viable. For candids this is often preferable as you don't intend to blow the image up that much.

For "really" hyper kids create 2 areas for play, in which to alternate, and then have your helper keep the kids busy in one place while you set up the second. Position yourself so that when the kids rush your second site they will briefly be in a focus plane with the toys/props you set for the scene. Pre-focus on the props and then call the kids into the scene. It works pretty well until you run out of toys/props.

---

*Ring ultrasonic focus motors often have proprietary manufacturer names like:

Canon – USM, UltraSonic Motor
Minolta, Sony – SSM, SuperSonic Motor
Nikon – SWM, Silent Wave Motor
Olympus – SWD, Supersonic Wave Drive
Panasonic – XSM, Extra Silent Motor
Pentax – SDM, Silent Drive Motor
Sigma – HSM, Hyper Sonic Motor
Tamron - USD, Ultrasonic Silent Drive

There may also be inexpensive micro-motor variants of the above named lenses that do not allow "full-time manual focus".

cwoodard

You can do this with the 5D as well but I think my hand isn't big enough to reach it comfortably. You can also use the ring to the right of the LCD below the joystick, and I find that MUCH easier to reach,however, there is no easy way, like with the joystick, to get back to center point. You have to turn the dial around and around and around. With both of these options, they dont seem to work until after I press the shutter button halfway. So it seems easier to just press the AF point selection button and then use one of them. But it still doesn't give me a quick enough option to get the shot on a moving kid. Hmm. Well I guess I just need to play around with it all some more

Dan7312 wrote: »

I don't know how it how it works on the 5D II but on the 7D you can configure the joystick/button on the back of the camera so you can move the focus point with your thumb while you are looking through the viewfinder to compose the image. So you might have to rummage through the manual a bit more, but hopefully someone else while chime in the the custom setting.

cwoodard

That's a great point about the cropping. I don't have the room in the studio really for that with this lens (until I can get another lens with a range better suited to my studio space) but outdoors I will try that. And since that's where the main problem is with focus/recompose & DOF, that sounds like it would help a lot. Thanks!

ziggy53 wrote: »

Focus, shoot and recompose through cropping can also work using the center AF dot alone. The 5D MKII has enough resolution and image quality that cropping in post is viable. For candids this is often preferable as you don't intend to blow the image up that much.

ThatCanonGuy

Configure the camera so that you can change points easily, quickly, and without taking your eye away from the viewfinder. With newer cameras I think you can do the joystick, but like you said that might not be the best option for you. On my 1DII I can change points from center to edge in less than five seconds(I use the + zoom button and the two dials).

I know that's not quick enough. I usually keep my point in the center or halfway from the center to the edge. Yes, good point about cropping. That's the beauty of 21.1mp . BUT, cropping will degrade IQ a little and it's not always the best thing to do. When shooting full body portrait-oriented shots (mainly sports) I try to keep the point near the eye or at least on the face of the subject. Doing upper body shots with landscape orientation, I will keep the same AF point (It's about halfway from the center to the edge) so that the subject is not in the very center, or I will use the center point sometimes.

Keep in mind that I'm using 45-point 1D AF in which I can trust every AF point to be fast and accurate. As far as I know the center point on the 5DII is the only reliable one, at least for action. That's a factor here. I would try a point halfway from the center to edge and see how it does. Let us know if the outer points are really as bad as the Nikon fanboys say they are I realize that the center point is cross-type at 2.8 (right?) but I would use the off-center ones if possible.

Sam

I can tell you that focus and recompose can work very well. Another thing you may consider is to use the center focus point and if shooting at say f8 and a focal length of 50 mm to 70 mm go ahead and focus on the center of the body or what ever is closest to composition you want.

Using a 5D II at f8 and 50 mm with the subject 15' from the camera your DOF will be over 6 feet. If your shooting at f8 and 70 mm your DOF will be just shy of 3 feet. Still plenty if your focus point was say 6 or 10 inches in front of the face, or off because of focus recompose. Even better if you can shoot at f11.

Of course once you start shooting at wide open apertures it's a whole different animal.

If you do know what the pose, orientation will be then yes i would use the closest focus point.

Sam

cwoodard

Would you use the center point Sam? Or one a bit further out? I was wondering if maybe I should try shooting with a smaller aperture and then if needed, blur the background later in Photoshop.

I just took the camera out back with the dogs and the kid and took a bunch of shots.. AV, f5.6, auto ISO, focus-recompose using an AF point top middle right, closest to center point. I'll report back with what I found after I look at them

cwoodard

Well. I had a lot of blurry photos, as I expected, because of moving targets. What I was pleased about though, was that when I got a shot when someone was still, the parts I wanted to be in focus were in focus. I don't see any photos where one eye was in focus and one wasn't, etc. Focus-recompose using an AF selection point just outside center seemed to work very well. I guess next step is to try playing around with AI Servo to reduce the number of blurry shots. Maybe TV so I can freeze the motion better? But then I would potentially have to do a lot of DOF faking in Photoshop afterward. Any suggestions about that?

If you're curious, I posted some of the shots. Completely uncooperative son. Figures Only retouching I did was some recropping or exposure fixing.

Thanks for all the suggestions!

ThatCanonGuy

You need to use AI Servo for moving targets, cause once they move after you focus, they go out of focus. As for freezing motion, when I shoot fast dogs I like 1/1000th to stop them. For kids running around, 1/640th will probably do. I recommend either shooting in Av and watching your shutter speed (adjusting ISO when needed) or just shooting manual.

Sam

cwoodard wrote: »

Would you use the center point Sam? Or one a bit further out? I was wondering if maybe I should try shooting with a smaller aperture and then if needed, blur the background later in Photoshop.

Let me say that there is no one answer. That said, if possible, I would use one of the outside focus points that got me closest to the desired composition, and I would use the f stop that produced the look I was after.

I just completed a shoot of young Chinese dancers at their dance studio with studio lighting. All instructions were given in Chinese. I don't speak Chinese. I had little to no idea if the forth coming pose would be portrait or landscape. Heck I didn't even know half the time when they planed a jump or other movement. They switched from pose to pose very quickly. In this instance I used the center focus point with an aperture f8 to f10. I focused on the center of the dancer or on a hand arm closest to the camera. This allowed me to rotate between vertical and horizontal in a second. Since the children would tend to pose at different distances in relation to the studio lighting I controlled the exposure with the aperture.

When using wide open apertures I pretty much always use the focus point closest to the desired composition. With the 5D II I can also use the center point, shoot a little wide and crop for the composition.

Sam

TangoJuliet

I shoot a lot of moving subjects using the 7D. AI Servo is a must! I'm usually shooting model airplanes, or real airplanes and helicopters so off-center compositions aren't the norm (unless I'm shooting something static, then I'm more creative with the composition and use the joystick to move my focus point). With the model airplanes I can use a faster shutter speed (+/- 1/1000) and still get good prop blur because the model engines turn at a much higher RPM than their full size counterparts while keeping the model sharp, but I have to remember to use a slower speed for the real airplanes to get the same results.

Qarik

Unfortunately the apread of AF point in the 5d mk2 is no that great. If you want to shoot near wide open though and get the "eyes"..you can't be adjusting every shot. You have to setup the an outer AF point for example and compose the shots as you go. I shoot a LOT of children and what I do is set the focal point in one place in portrait mode, compose and shoot over an eye, repeat for other kids/scenes..then move to landscape mode pick a focal point, shoot severla kids, scenes, pick another point on the other side, repeat...

This way you get different compositions but still NAIL the focus. I can get away with a few shots where I see something..move my focal point, compose and snap away..but 70% of the time the kid is gone by then. Stick to one focal point and compose in the viewfinder..not in your head.

cwoodard

Can you use AI Servo with a manually selected AF point?

Thanks so much for all the great advice. I appreciate it!

cwoodard

(lousy weather and demanding three year old kept me from doing some more playing around today and answering that last question for myself!)

ThatCanonGuy

cwoodard wrote: »

Can you use AI Servo with a manually selected AF point?

Thanks so much for all the great advice. I appreciate it!

Yep. If the camera is in AI Servo mode, every point will do continuous focus.