Large family portrait - Help Needed

I have a large family (18-20) group portrait session coming up and need some help. I have always used my 24-105 L for family portraits and my 85 1.8 for seniors and other small 2-3 people groups.

What would my 85 1.8 be like for a group this large?

Of these two lenses which one would you use and what advice (settings, etc.) can you offer as this is my first time with a group this large.

Thanks in advance.

D.

Your 24-105 should handle the job nicely. Be sure to get up high on a ladder, that will help as well. You didn't say what you have for lighting, but if the 480 is it, you might want to make use of the best natural lighting you can find, which would be late day light. If you have the right location, you can group them in family groups. Or you can arrange them in five layers of four, or four layers of five. You will probably want at least an f8 to keep everyone in focus, it depends on your posing. Don't be afraid to go to a higher iso if that is what you need to do to get the shutter speed/aperture combo you will need.