What fstop would you use if you had a bride walking in from about 30ft away and you had to keep her in focus while she made her way down the aisle?

I am going to be standing directly in front of her in a stationary position with my 5DMK3 on a monopod.
I don't have a viewfinder for my 5DMKIII yet as I am saving up for a Zucuto.

Thanks

There is no answer to that, it depends on the intensity and the direction of the light. Take your camera out and shoot, shoot, shoot. Talk to the camera constantly, noting your settings for any given shot, Scrutinise the shots to get to know just how your camera/lens combo is performing in different lighting situations. As I have said many times before, you must understand your camera, you must know how to get the best out of it, in any situation. Eventually, and after a great deal of practice it will all come naturally. My father was my mentor back in the sixties, he drummed 4 words into me. COMPOSE - EXPOSE - FOCUS and SHOOT. After 3 years he let me shoot solo on commercial jobs, I count my blessings to this day for his teaching. What I am trying to say is, it wont happen overnight. You really do have to be at one with your equipment, you need to pick it up and be confident that you can deliver the required result with any given camera. There are very rarely simple solutions, most shots, video or stills dont just happen, they are composed, exposed, focused and shot by whoever is behind the camera.

Thanks Colin!

I guess panic just kicks in sometimes :)

Thank you for the post of the day, Colin -- and it ain't even noon yet -- that was excellent.

Great post, Colin! :)

Tariq, you'll find it extremely difficult to maintain accurate focus with the bride if you only judge when to re-focus by looking at the rear screen. (and she will also not thank you if the biggest day of her life is out-of-focus).

A loup fixed the screen is a must-have item in my opinion, and I would suggest that you buy or make a cheaper option if you have to wait too long to save for the Zucuto.

There are many options to choose from, such as the LCDVF, Hoodman, and others. I use a Hasselblad chimney finder which clips quickly and safely on-and off the Canon 5D. It is very high quality and a wonderful aid for manual focus, and has built-in diopter adjustment.

Here is a good DVinfo link to a discussion (with photos) of finders for the 5D/7D including my Hasselblad:

http://www.dvinfo.net/forum/canon-eos-5d-mk-ii-mk-iii-hd/478373-lcdvf-fell-off-my-5d-took-lcd.html

Thank you Chris and Tony for your kind comments, much appreciated.