I am just starting out in photography and when I am focusing on one point (like a single person portrait), I can get really sharp photos. However when I am photographing a scene or a group of people, the photos come out blurred, every single time. Does anyone have any suggestions? I am probably using the wrong camera settings as I am still learning those.
One possibility might be that you are using some kind of "auto-detect" focus setting, which works good for single portraits ("face-detection" automatic setting for instance) but for group photos, the camera makes another guess at what is supposed to be the focal point and the optimal settings for that scene. Looking into learning how to use your cameras focus modes and taking manual control will probably net you good results.
Of course, you might have a lens that is very "soft" when focusing on distant objects, or might also have some mechanical defect, and this might complicate matters, but it's also not that likely.
I'm going to toss this in as an answer - but I'm really hoping that OP edits to clarify some of the parameters of the question so that it can be answered for their exact scenario.
I'm assuming that you are using a DSLR with a kit lens.
When shooting a portrait of a single person - you have to worry about a single focal point, and can even use extremely shallow depth of field - the kind where the eyes are in focus but the ears aren't. You're probably zooming in as well - My experience with kit zooms is that they tend to be sharper at the telephoto end.
When shooting a group, you're now zoomed out and you have people at varying distances to the camera. You need to set a single focal point and then make sure the Depth of Field (DoF) covers the rest. If your DoF is too thin - then some people will be in focus while others will not be.
Without knowing more - this is what I believe your issue to be. Simply using too large an aperture for the group at a given focal length, causing people to be out of focus.
I would suggest focusing on the nearest person to the camera and using an aperture value of f/8 to pull everyone in. Having no knowledge of your gear - I can't say if this will actually work, but it's a place to start.
You will need to set your camera's aperture value manually - so I suggest reading more about Av (Aperture Priority) mode. Stopping down to f/8 will also help sharpen the photo - if the auto settings were trying for wide open.
Topics that you should read more about:
There is a plane of focus. With normal lenses, it is parallel to the camera sensor, so everyone that lies on the same plane will either be in focus or not.
When you have a single person ahead of you and you get a sharp image, it is because that person is on the focus place. If you add more people to the shot, they must be on the same plane to be exactly in focus. When they are not all on the same place, some people will be less sharp, this is simply how optics work.
What you must do then when you have a group and they are not all standing alone a plane parallel to the sensor is to increase depth-of-field. You do this by using a smaller aperture, which are denoted by larger values. So F/8 is smaller than F/2 and therefore gives more depth-of-field. To compensate, the camera will choose a slower shutter-speed, so you should raise the ISO to avoid blur from subjects moving.
People who are not on the place will still be less sharp than the ones along it. This is normal. What the increased depth-of-field does is slows the transition from the focus-plane outwards, so people out of the focus place wil be less blurry.