Focus Mode?

What focus mode do you use for taking shots of people walking down the center aisle? Since they are moving would the AI Servo AF mode be best?

AI Servo -

The distinct advantage you have with this is continuous AF all the time including when using flash.
If you change to OneShot mode to get the speedlight AF assist beam the pics may be soft if you are shooting @ f2.8 or lower.

Of course everything is relative and flash does freeze the action but there are instances when they just move ever so slightly and when the flash freezes the action there is a bit of ghosting on the outline of the subjects if you look closely.

In the end the way I look at it is that I have the advantage of flexibility.
I know I have to have AI Servo on if I don't use the flash anyways.
At the same time the added benefit of AI Servo constantly checking the focus is a benefit when I do use the flash and I'm forced to use a lower shutter speed so I can allow the ambient light in (that way everything does not look like a bat cave).


This is the case because the AF assist beam on the speedlights in one shot only mode will only check the distance to subject when you press the focus button.

To me it is the best option for the walking down the isle part.
Most lenses that Wedding folk use like my 17-50 can focus in most churches on their own.

As a backup on my XTi I keep the Sigma 20 1.8.

I see you have the 18-55 2.8 IS which is oustanding.
You should have no problem focusing in everything but the darkest places.

At the reception it is another story and I use OneShot since you have to leverage the AF assist beam from your 580II and you can't do that in AI Servo.

I can tell you that I've taken pics of the groom and his mother dancing at the reception with my 85 1.8 @ f 2.0 using my 10D and One Shot with the 580EXII using the AF assist beam and they came close to perfect.

I did see the ghosting line in their outlines on 2 pics when I looked closely but I was not very subtle.

It's a nice change from the pics I see taken at that particular part of the party where everything including the wallpaper pattern on the wall is in focus

Was wondering about this myself. Great info!