Focus+recompose

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Recently I've been selecting picking the different AF points on the 5D2 to ensure that I move the focal plane as little as possible when composing the shot. However, I was wondering if there were any other methods/functions that could help me further when taking portraits. Also clicking through a different AF point each time is a bit of a pain.

Would any of AI Servo modes be of much use here?
 
Apart from centre then recompose, i think you are already do the best thing.

The thing with auto point detection in AI Servo though, is that it finds focus with the centre point first and then uses the outer ones if needed, this could work if combined with back-button focusing, but tbo i still think your first two ideas were the best ones.

Have you had more accuracy when using the peripheral focus points?
I agree that changing point all the time is tedious, dunno what its like changing on a 5d2 though.
 
Not sure if you're aware but the reason that focus recompose is innacurate is that when you focus on a point 10 feet away you are effectively focused on a flat plain 10 feet away so some of which you are precisely focused on wil be, perhaps 11 or 12 feet away as you look away from the centre of the scene.

The problem with focus recompose is that twisting and tilting the camera you knock this flat plain out of kilter and depending how far you have to move the centre af spot from it's original location i.e. the sitters eye you will get varying amounts of focus error.

In practice centre af spot recompose works well for full length subjects at normal apertures but if shooting head and shoulders at f1.4 or f2 error will often be apparant.

I suggest you set the camera in the portrait format i.e. vertical and chosse the af spot nearest to your sitters eye then focus recompose with a fairly minimal shift.

The great thing about digital is the short feedback loop, you can try out various options with a willing sitter or a felt pen mark on a football and check the results. If you can stick to the centre spot, great, time saved, and a more spontaneous image.

I agree with the earlier post, afc will be disasterous, for a portrait formal, or informal only the eye, nearest or brightest is the critical focus point (except possibly hands in some shots).

Good luck, John
 
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thank you guys for your help. Just to clarify, what I am asking about is if I switch to one of the servo modes that follows the subject, if I use the center point to focus and then recompose, how likely is it that it will track the subject accurately?
 
While using AI servo, if you move the chosen AF point off the subject.... then the camera will refocus and the subject will be O O F ....

You would be wiser trying to try to understand where the subject is moving into and using an AF point other than the centre point (to suit the 'recompose' that you are after)
 
using the joystick is much quicker.

Other options that work very nicely are cropping in post (you have a 5d2 so have pixels to spare) use the closest point then instead of missing focus wide open and recompose in pp

I do recompose a lot too but v rarely at wide apertures, sometimes I manually focus, sometimes I use live view as you can move the focus point anywhere (its software based). Its just a matter of using the most suitable tool for the task
 
Back button focussing makes my life easier.
 
Legacy said:
While using AI servo, if you move the chosen AF point off the subject.... then the camera will refocus and the subject will be O O F ....

You would be wiser trying to try to understand where the subject is moving into and using an AF point other than the centre point (to suit the 'recompose' that you are after)
Click to expand...

no one ever recomposes on a moving subject, to recompose you either use one shot or back button AF
 
david1701 said:
no one ever recomposes on a moving subject, to recompose you either use one shot or back button AF
Click to expand...

Agree - Was suggesting an alternative to you cropping in post....

e.g. an athlete runiing from left to right.... use left AF point with AI servo and track them .... (as if to give them space to 'run into')

:D
 
but they will have moved, which is the whole issue with focusing and recomposing as they will move from the area of focus to the middle of the frame and being out of focus, if you really felt like it you could prefocus but I'd just go with centre point servo mode for it and if it needs some cropping it needs some cropping, on of my portfolio images is a 16x9 crop of the bottom corner of the frame, I use it at 6"x9" (black borders top n bottom) to show wedding clients a lot and its sharp as sharp
 
one of the reasons why I asked this is, I am trying to cut down the use of flash at weddings and shoot more in available light, but that generally involves using teeny weeny apertures.

If I got this correctly, if I focus and recompose on any mode other than one shot, the camera won't adjust and keep the area in focus?
 
do you use back button af or shutter button af

I have my back button (only) set to AF, half press shutter is a meter lock and full press shutter takes the shot

I can lock focus and exposure independently of each other and shooting
 
david1701 said:
do you use back button af or shutter button af

I have my back button (only) set to AF, half press shutter is a meter lock and full press shutter takes the shot

I can lock focus and exposure independently of each other and shooting
Click to expand...

That's kinda what I wanted to say.;)
 
What's a normal camera? :D
 
david1701 said:
do you use back button af or shutter button af

I have my back button (only) set to AF, half press shutter is a meter lock and full press shutter takes the shot

I can lock focus and exposure independently of each other and shooting
Click to expand...

yep, I do all that.
 
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