R.J. has it right. Depth of field is what makes the sport finder work.
Balancing smallest possible aperatures, film speed and available light requires some thought and practice but can be rewarding.
The old press photogs often used flash bulbs which have really impressive guide numbers to be sure they'd get the shot. Most modern flash units don't normally reaching these high numbers and bulbs are not convenient to get and can be pricey.
Also the available film speeds in large format tends to be ISO 400 and slower. This limitation coupled with the fact that f5.6 is often wide open for a large format lens, you see how much tighter your exposure boundries can be compared to 35mm.
However, I find Tri-X 320 processed in Diafine lets me work with it at about ISO 1000. Real nice for keeping the aperatures small when shooting handheld or when I use heavy filters. Since it takes more than a liter of developer, I like the longevity and reusability of Diafine as compared to processing in other developers that can also push the film this far.
Oh, but those big negatives! They're so cool.
