This is my first question on the Photography stack. So please forgive me if I dont sound too technical.
I have a Nikon D5100 and a 18-50 mm F 1.8 Lens. I enjoy taking pictures of my 13 month old son who is constantly on the move as he just started walking. I usually try to use the Manual mode and set the aperture > F2.5 and shutter speed(usually 1/2 or 1/8) to suit the light. But I usually have a problem when I encounter low light. If I use the lowest F stop, I get blurry images owing to lower shutter speeds (I dont have a tripod yet). I have used the Sport mode with some good results, but I would like to have more control of my images.
My question is, what other modes I can use to remove the bluriness and if having an external flash would help.