A group of 5- 6 is well within the capability of your current flash gear if you utilize it effectively. The primary goals for groups are: 1) good expressions on the faces, 2) even light on the front of ALL faces so the expressions can be seen, 3) as few distractions from the faces as possible (i.e. hands, foreground, stuff behind/above the heads)
The ideal situation would be to shoot outdoor in an area where the sun can be used as backlight on the subjects while at the same time it shades the background:
That would allow you to do the job with a single flash on a bracket because in that situation the sky would provide a tremendous amount of wrap around fill.
If must shoot indoors that same strategy - backlight + centered frontal fill on bracket - is ideal.
There are simply too many pitfalls with group if a single-person lighting strategy such as short lighting (i.e. key 45 degrees from nose, fill over camera) is used. Short lighting requires precise positioning of the nose to the light to avoid a distracting nose shadow. With five noses in a photo getting them all perfectly aligned to a key light off to the side is very difficult, especially in a production line situation. When the key light is put off to one side and people in a group turn towards the center the people closest to the light wind up broad-lit with faces half in shadow and overexposed. Thus the better strategy for getting even light in all the faces it to put the light where the faces are looking - over the camera on a bracket. Then park your 420ex behind and above or off to one side for the back-rim light component for a look just like out in the sunshine.
to be honest, i was expecting an answer from you.
glad you did.
It will be indoor. I will probably use the 580 over the camera, and 420 off cause all guys will face the camera.
should I use a large umbrella (3 feet diameter) for the 420 ?
to be honest, i was expecting an answer from you.
glad you did.
It will be indoor. I will probably use the 580 over the camera, and 420 off cause all guys will face the camera.
should I use a large umbrella (3 feet diameter) for the 420 ?
An umbrella cuts output by about 3 stops and is rather cumbersome to use. I find the DIY diffusers are far more convenient and produce lighting which is just as flattering as umbrellas when used in a key / neutral fill configuration.
When you say you are planning to use the 420 "off camera" I'm not sure if that means behind or to the side. I'd recommend to test any configuration with the key light off to the side in front with a group of real people and compare it to my suggested strategy of keeping the frontal light centered.
Remember the broader goal in groups is just to see the small faces in the photo. Short (i.e., sideways key lighting) just is not a good strategy for that unless you have the time -- which you will not - to refine the pose.
Also, short lighting isn't the most flattering pattern for a full face pose for most anyway. It create asymmetrical lighting pattern over a symmetrical camera angle which results in the net effect being an asymmetrical face.
What you need to grasp is that the lighting pattern needs to complement the facial angle to make the face look slim and symmetrical: the two characteristics of faces which people of all cultures deem attractive:
Short lighting Ifront mask of face highlighted) complements an oblique view on a dark background.
Broad lighting (highlight on side of head, front in light tone shadows) complements an oblique view
Butterfly (key in line above centerline of nose) complements a full face view on both light and dark backgrounds
This has nothing to do with "rules". I know my suggestions often seem like rigid rules, but they are simply a suggestion to try first what has proven to work for many. I try to explain why things work, or not, so it is easier for those who see more literally than I do can see the underlying cause and effect. If the #1 goal is to create the most flattering appearance the most effective strategies will be those which make the face look most symmetrical and slim. There is also no rule which says one must always use the most flattering combination either, but developing the skill necessary to find the most flattering combination of angle and lighting pattern and know when you don't have it is a very useful one to have.
