What Lens

What is the best lens to use to take a photo of a large crowd of about 400 people?

Depends on the room you have. If you have plenty of room a 35mm could work great. If the area is tight you may have to go with an ultra wide like the Tokina 11-16mm and have to make sure the camera is perfectly level to minimize warping.

Ok, thanks. I'll check those out.

I do have the Nikon 55-300mm. I try that one. Again, thank you.

Again, I'll reiterate the answer 'depends'. We have no idea how close you will be to the group. Distance is the key factor here, as well as your perspective in relationship to them.

If you're relatively close, you'll need an ultra-wide. If you can step back a bit, you might just need a wide-angle. You may find a 50mm is perfect. If you're some distance away, a 105 or so might work best.

Without any further details, we're just shooting in the dark here.

Yes, I understand.

Keep in mind Tonij that our D5100's are DX format cameras, so a 35mm DX lens will yield the same as you'd see with your eyes. For a true wide angle lens, you'll need to go with something below 35mm such as that Moab Man recommends. If you have the 18mm-55mm Nikkor "kit" lens, you might find it suitable. Let us know how it all works out. Thanks.