Jim Bianco wrote:
I am going to take a group photo of my class reunion in a dance hall, what lens and what settings would you guys prefer at least 50 or more people., help is greatly appreciated.
The kneejerk reaction is to go to the widest lens possible "to get it all in". The problem is that while ultra wides will achieve the goal of "getting it all in" but they will record the scene with volume anamorphosis (unnatural subject elongation towards the corners and edges)and extension distortion (subjects in the foreground are recorded disproportionately larger than the same sized subjects in the background) - both of which are very undesirable for group shots.
https://www.youtube.com/watch?v=9ZmI94uL4KkA more successful result can be achieved with a more normal lens - 50-70mm - and the best aperture, usually F5.6-F8 - on a full frame camera. Everyone wants to see themselves, so this image will likely be viewed at close distances, so focus and sharpness are critical.
The most successful result will likely be shooting this as a stitched panorama, with camera in portrait mode and anywhere from 3-5 shots overlapping them about 50% "to get it all in" without the distortions. A couple of added benefits are that your resulting image will be very high resolution - much more than if you shoot it as a single shot and if you take multiple shots for each image panel, you can pick and choose the best of each before merging.
https://www.google.com/search?q=pano+for+large+group+shots&rlz=1C1CHBF_enUS908US908&oq=pano+for+large+group+shots&aqs=chrome..69i57j33i160.12211j0j7&sourceid=chrome&ie=UTF-8#kpvalbx=_p8tSYtiWBfCwqtsPvJi6kAM28Lighting a very large group is challenging with small equipment. If you can't find a nice outdoor setting with steps and the shady side of a building, then maybe the hall has lighting that they can work with you on. Try to have no more than 3 rows - to help ensure everyone is in focus, front to back.
The shot below was a difficult one, and goes against my recommendations for lighting, lens, composition etc but it was the best I could do under the circumstances. It was in a small meeting room, awful ambient light, and limited places I could photograph the audience of about 30 from. I set up 3 umbrellas, all aimed high at the walls - one behind me over my right shoulder, one at the rear left above the window, and another rear right. I used a 10-20mm lens on a 12 mp cropped camera (Nikon D300) at 11mm and F6.3, and I placed myself as far away as I could from the nearest subject to minimize distortion.
When reviewing the raw files, I was unhappy with the uneven lighting, so I used some radial and linear gradients in Lightroom to achieve a slightly better balance.
I don't have any examples of larger groups using a pano, which is why I didn't post one.
Good luck! Post results!