Distance from subject???

[Scatterbrained]

If you understood aperture, ISO and shutter speed then shooting at specified distance should not be
a problem. The distance between a camera and the subject is calculated based on aperture, ISO and shutter speed.

Or you can use a tape measure. Or just guesstimate. I'm really curious as to how aperture, iso, and ss can tell me my subject distance?

Shooting at f1.8 is allowing a lot of light into the camera. You can make the adjustment by controlling the speed of the light allowed into the camera. To get your party in focus at a distance of four feet or more, I would suggest you use a
tripod to minimize camera shack, if you have one, focus directly on the eyes, once they are in focus, then shoot..

This has got to be one of the more confused things I think I've ever read on a photo forum. FYI, if you can control the speed of light, you are damned impressive. Beyond that, a tripod won't compensate for too shallow a DOF.

Right now I think the OP needs to go through her owners manual front to back. If that is too tiring a task then at least pick up Bryan Peterson's "Understanding Exposure".