Focussing quickly without using the prism

[thehouseflogger]

I have been using my camera with a 24mm 2.8 and I am slowly learning how to use it in many situations that are frequent in my work.

I am trying to not use my Canons during the wedding speeches phase as I want to be less imposing when I get up close. So the 24mm is just fine for width of view - I can get in lots of guests and the bridal party at the top table and the speaker. What is difficult for me is to figure out where I should focus as I invariably have to recompose in the viewfinder before taking the shot. I am usually sitting on a stool just next door to the top table at the same height as the guests.

I have found that at f2.8 I can set the lens distance scale to round about 12 feet or so and the depth of field allows quite a good range of in focus heads, from 5 or 6 feet to infinity.

Metering seems fine as a sea of heads in a marquee tend to have a pretty average brightness level.

Does anybody have a rule of thumb which they use in this situation - perhaps somebody has a technique that works.

I would be very interested to learn from those out there who are more skilled and experienced than I. Thank you.

[manolo]

I am not an expert but what I would do is focus bracket with feel as you are looking through a viewfinder. You could even have an external viewfinder.
Some pictures this way give a nice sorprise when you look at them in the computer.
I would tend to focus more to the nearest than to the ferdest