I am an beginner photographer and I was "hired" to cover a company final year party. The idea is take group shots or portraits and print "on the fly" the pictures, then the guests can see and take the shots during the event.
As we can see on the picture the room is pretty long and have a high ceiling. I've seen that portrait photograph or groups pictures looks much better when the flash is position to the ceiling, but in this case I do not have this option. However the skeletons and dinosaurs can help me to create some cool compositions.
Because I will not post process the images, the quality have to be enough to print in a normal size 10x15.
Question What will be the best setup and position for the flash?
The ceiling is white, but is probably too far away to bounce your flash unless you have a very bright flash. Your best bet is probably two flashes and soft boxes or large reflectors. If possible, setup both on stands, one left, one right and ideally a third behind a shot, but one left and one right or even one on camera with a largish softbox and one off camera to the left or right to give key lighting would work.
If you are stuck with just the one flash, moving it off camera with a softbox would be good, or if you need to, on camera with a softbox can work as a last resort if you really need the mobility and speed, but quality will suffer a bit.
I'd also recommend reading up more broadly on three point lighting. If you can't do the back, you still really want a key and a fill to give nice balanced shadows to give depth and avoid dark spots in the image. Be sure to adjust flash output power or distance between them and the subject as well so that your fill allows for gentle shadows to give the image depth.
Just to keep on track what's happening on the event and how was the result:
The location was, as expected bad to take pictures, with the giant dinosaur in the middle, making hard to "put" people on good spot to shot. Also, on the back, the walls and some glass made a funny and bad reflection.
Because we were printing the pictures as I was shooting the pictures needed to be a bit overexposed to looks nice printed.
In general the result was good, but I had few challenges and things to improve for the next time:
Now is prepare myself, study, practise and be ready for the next challenge. :-)