I've read a couple of explanations regarding which mode to use: AI Focus, One Shot or AI Servo. I'm still a little confused. I took some photos of 5 year old twin boys this weekend and needless to say MOST of them were out of focus. Would I have been well served using my AI focus? Since I'm a beginner, I'm sure I'll get a few groans as why in the world I'd take photos of whirling dervish in the first place! LOL!

Hi, Kim. This might be obvious, but since you say you're a beginner, I'd recommend that the first thing to do is make sure you're diagnosing the correct problem. If your boys were running around (or whirling), the problem could be that you weren't using a fast enough shutter speed to freeze the action, resulting in blurry kids. If that's the case, no autofocus option will help. Have you ruled out shutter speed as an issue?

I was shooting 98% AV. I had taken some shots on Friday and used shutter priority for a couple of frames, but, looking at the replay, the results were actually no better than when in Aperture Priority. I THINK I had the shutter adjusted to...between 15 and 30. (I just went to look at my folder...I ERASED all those shots) Should I go as high as the 100's for movement shots? 1000's? I kept my ISO at 100 for all the outdoor shots and 200 for some shots inside (we were at the zoo at 2:00 pm)I am SO frustrated! The majority of my shots come out so blurry...all the time, I'm wondering if my CAMERA needs to be "fixed!" LOL! It doesn't! I just don't know what the hell I'm doing! I need to PRACTICE focal length as well! I think that has a lot to do with all my errors! I bought a Canon 100mm macro, because I LOVE macro, but I can't get those right either! UGH! It has been BEATEN in my head to use a tripod for macro work! What a bummer! I guess I will HAVE to conform! )
THANK YOU so much, David, for your input! Nothing is obvious to me at this time, so, any direction is more than welcome.

Shutter speeds of 15 or 30 are usually much too slow for hand-holding the camera. At that speeds, any little movement you make translates to blur in the photo. And it's definitely too slow for freezing movement if your kids are running around.

A good rule of thumb for knowing whether or not you can safely hand-hold at a given shutter speed is to consider your focal length. Use a shutter speed that's at least the same number as your focal length.

For example, if you're using a 50mm lens, pick a shutter speed that's at least 1/50th of a second (1/60 is the closest standard shutter speed). If you're shooting at 24mm, you can get away with hand-holding at 1/24 of a second (1/30 is the closest standard shutter speed). And if you're zoomed in with a 200mm lens, you probably shouldn't try hand-holding at slower than 1/200 of a second (1/250).

Speeds of 60 or less are probably not fast enough to capture your kids if they're running around. Experiment with high shutter speeds and see how those shots come out.

Don't worry. The more you shoot and play with your settings, the more you'll get used to understanding how to get the look you want.

Once again, thank you for the lesson! There is SO MUCH to consider, remember and think about before you press the "button", eh? I'll practice this today. I've heard it before, it just takes some time to apply!
Have a great week.
PS~The TWINS are NOT mine! LOL!