Pics blurry with 50mm f1.4 lens

I'm new at this. I have a 50mm 1.4 and I can't seem to get sharp pics. Maybe because my kids move around alot? I was taking some shots in our living room tonight and none of them came out clear. With low light should the f-stop be higher or lower? Any advice? Here's an example..

With low light, you want smaller f-stop number. What's more important in low light is that you keep your shutter speed above 1/60. Please post your EXIF data for that pic.

Looks like that is what happened. the shutter speed was to low. In low light you should bump up the iso and use a lower f-number.

f-1.4 = large aperature which lets more light in
f-8 = smaller aperature which cuts the amout of light.

What is EXIF data?

If your using anything below f2 you'll find that the depth of field drops off dramatically, therefore not much area will be in focus.
If your kids are moving around quite a bit it'll be more difficult to get them in focus unless you use around f2 upwards.
This photo was taken using f1.4,you can see that the area in focus is quite small.

HOSTED PHOTO
please log in to view hosted photos in full size.

If you are shooting at 1.4, the DOF is extremely shallow, and everything will be soft except for what falls in that very narrow plane.

Try shooting one subject, select the center AF point, set that AF point over the subject's eye, and take the picture.

The 50 f/1.4 is a very good lens and can take some very good pics but technique is very important especially in indoor low light situation. If are use to shooting Digital P&S cams you need to relearn how to hold the camera. Support the camera from under the lens w/ your left hand, elbows down and hold the grip of the body w/ your right hand. Depress the shutter release button gently so that you don't jar the cam down. Hold your breath when you are ready to release the shutter. These technique will help stop camera shake a little.

Shooting at f/1.4 is very difficult at first because the in focus area will be very small. You need to find a point that you want to be in focus and lock on to and reframe the image before releasing the shutter. A good way to do this is by selecting only one focusing point and use that point to focus. There should be a solid green light on the lower right side of the view finder to confirm focus lock. Good luck and have fun.

The exif data is all of the info attached to that photo. It will include things such as shutter speed, f-stop, lens used, iso, among others. From the looks of it, you probably shot at too slow of a shutter speed. The basic rule of thumb for avoiding camera shake is 1/focal length of the lens. So, with your 50 it would be 1/50 of a second shutter speed to avoid blur. That rule of thumb is a carryover from film, and for digital it is usually wise to figure in the crop factor of your camera also. With the 1.6 crop factor on your XTi, your 50mm lens is essentially now a 80mm lens, so your minimum hand-held shutter speed should be somewhere around 1/80 of a second. To achieve that, you'll need to either increase your iso, or open up your lens some (use lower f number)

The DOF from a 1.4 is tough to handle yes, but that photo looks like subject motion blur, not OOF.

Try this.....
Put your camera into Av mode.....select the aperture to be 2 or so, and bump ISO till the shutter speed reaches 1/100. Fire away...........

This was taken at f/2 with my 50mm f/1.4 lens.
you can see that even though the two boys were together the one in front is out of focus.
I focused on the boy at the back as i wanted him to be in focus but as pointed out, you really have to be careful what you focus on if you are using large apature's.