best bet for in-focus portraits

So im getting increasingly frustrated with my 5d2 and its ability to consistently achieve focus when using the outer points. I've MAd my lenses and reset it all because its not the lenses. Its not handshake, I know what it looks like, the images are soft, not blurry from motion. if i take 3 shots of the same pose, using the same focus point the camera may miss one, slightly, sometimes it get the eye dead on, sometimes it get the eyelid, sometime the top of the cheek. shooting shallow dof this is a big problem.

so im ready to look for alternatives and before i go out and buy a 5d3, which of these option would likely produces the best results.

1. using center point only and cropping in post for composition.
2. using center point only but using al servo and recompose.

with using only the center point i get much more accurate AF but i may lose quite a bit of image area, especially for full body shots.

with center point and al servo, i dont have to crop but will the camera track and eye effectively and im not sure I will get the focus confirmation either?

also would back button focusing help at all?

The outer points should be OK in good light...
Focus and recompose is not usually a good idea if you are using a very shallow depth of field... Using centre point and cropping afterwards should be an OK solution. but even more reliable would be to use manual focus if it is portraits that allow you the time to do so...

With centre point and A1 servo the camera will refocus as soon as you recompose so no benefit there..

For non-moving subjects such as posed portraits, I doubt that back-button focus would help with the accuracy of focus.

With very thin DOF, focus-and-recompose probably won't give better results than what you're getting now. It'll probably wind up back-focused more often than you find acceptable.

If the camera is not moving AT ALL, and the subject is not moving AT ALL - for instance, when shooting products with a camera on a tripod - then live view and manual focus will get the most precise results. However, when you're using a razor-thin DOF, if the subject moves even slightly, the focus will be missed - if you manually focus, then the subject shifts or breathes or leans away by just half an inch, then the focus changes from the eye to the cheek, which is exactly what you're trying to avoid.


I don't have any great advice. I'm of the opinion that if you're shooting portraits with razor-thin DOF, you're just going to have a lot of focus misses. Such is the nature of photographing a living, breathing subject.

You should post a few examples with the EXIF data intact so people can see what is going on. I world never use AI Servo for a portrait with a stationary subject. In fact, when I shoot a portrait or group shot, I often flip into manual focus mode after acquiring focus so I can better watch for the perfect instant to snap. Are you using a wide-open prime w/ a very narrow depth of field? why? Or, more precisely: are You sure your entire subject is within the narrow depth of field?

I'll throw out an idea. Rent the A7R2 with the 55mm lens and give eye focus a try. The AF system will lock onto the eye and then track the eye as you ars the model move. It's basically 100% accurate and the focus is pin sharp on the eyes. I used to shoot portraits with my 5d2 and like you it frustrated me to no end. The eye focus on the Sony is a breakthrough for portraits. I shot a musician during a performance nd my hit rae amazed me.

For non-moving portraits, I wouldn't use AI Servo unless you're shooting mobile/handheld. Servo is a predictive algorithm that constantly adjusts the focus instead of actually locking focus at a particular point; which could very easily account for the variation you mention between 3 shots.

Also, as mentioned focus/reccompose + AI Servo just doesn't do any good here; the camera will refocus as soon as you recompose.

I find that BBF helps ease of shooting, in general, but isn't something that's going to help with image results, really.

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don1163 wrote in post #17918058
With centre point and A1 servo the camera will refocus as soon as you recompose so no benefit there..

Not if you use back button focus, it won't.

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Tom Reichner wrote in post #17918199
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Not if you use back button focus, it won't.

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that kind of what I am wondering. If i set BBF and the use the center point to attain focus, when i recompose, wouldn't the camera follow the eye?

mike_311 wrote in post #17918249
that kind of what I am wondering. If i set BBF and the use the center point to attain focus, when i recompose, wouldn't the camera follow the eye?

No. If you are in One Shot, the plane of focus would lock and then shift relative to your movement of the camera and if you're in Servo, it will continue to focus at the active focus point while you recompose and therefore pull focus away from where it was when you began moving the camera (as long as you are holding the focus button down).

mike_311 wrote in post #17918249
that kind of what I am wondering. If i set BBF and the use the center point to attain focus, when i recompose, wouldn't the camera follow the eye?

No, as soon as you let go of the back button it stops following everything and locks in at that distance.
Might be worth a try - it's what I used exclusively on my 5D classic with thin DOF situations.

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How is focus-and-recompose different in AI Servo w/ BBF than just using One Shot? Sounds like essentially the same thing to me...

Snydremark wrote in post #17918270
No. if you're in Servo, it will continue to focus at the active focus point while you recompose and therefore pull focus away from where it was when you began moving the camera (as long as you are holding the focus button down).

I think you are off on this. If you are in ai servo and lock focus on an object and it leaves the focus point it should "hand-off" focusing duties to another point.

travisvwright wrote in post #17918936
I think you are off on this. If you are in ai servo and lock focus on an object and it leaves the focus point it should "hand-off" focusing duties to another point.

yup, as long as all points were active before starting to focus. If you have just center point selected it would act as snydremark said.

Not sure how well all points works with 5DII/6D style focus points that are fairly far apart. If it were a bird in space, yes it works, if it just an eyeball, not so sure.

Tom Reichner wrote in post #17918271
No, as soon as you let go of the back button it stops following everything and locks in at that distance.
Might be worth a try - it's what I used exclusively on my 5D classic with thin DOF situations.

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This is correct - however, remember that the focus distance isn't simply the distance from the sensor to the subject, but the distance from the sensor to a plane parallel to the sensor.

When you recompose, the location of that focal plane changes, even if the subject hasn't moved. This is the cause of focus-recompose errors.

If the subject is very far away, the error is minimal; if the subject is very close, the error can be significant.

http://i.stack.imgur.c​om/sQLmH.jpg

First, i just need to try this out on my own and plan to in the next couple of days.

this thread was started as discussion to see where i should focus my attention it getting a higher keeper rate and it seems that there is a big disparity in whether or not al servo should even be an option for me to consider and i dont understand why. I dont use al servo so I really have no idea to details of it in practice, but i do think i understand the fundamentals of how it works, if i'm off base please correct me.

You lock focus with an active point and the camera should track that focused area as it moves around the sensor. If i use the more accurate center point, lock focus on the eye, continue to hold down the button and recompose i dont dont understand why the camera wont track the eye until i fully press the shutter. Its not focus and recompose in the sense that my DOF will be changing and the distance of the eye to the sensor will change during the compose. I would expect the camera to adjust the focus distance as the eye moves to the new spot in my composition.

whether the camera is effective at tracking the detail of the eye as it the other less accurate focus points take over and result in a higher keeper rate is debatable.