I have the cheat sheets for the 50mm lens, and they have been my go to. I have a very active toddler and I try my hardest to keep my focal point on his face or in his eye to keep the subject clear, although for some reason I still get blurry pictures from time to time. I use the cheat cards for child portrait. Should I use a different card, or do I just need to really focus on keeping my focal point on? Is that the whole problem to begin with?
Comments
A couple of possibilities:
If you are tracking a subject, try to push the shutter button half way in advance of your shot, so AF has time to adjust, and to begin tracking. Then try to follow your subject.
Practice panning as much as you can, so that you're moving the camera smoothly as the subject moves. The more you can keep the subject in your focus point, the less work the camera's AFC has to do to track.
If 3D focusing loses your subject often, try dynamic area. 3D is often better, but because it uses color information and tracks in a different way, sometimes it can jump to the wrong thing, especially if your toddler does not stand out well against his background. Dynamic area is not as smart, but sometimes it's harder to fool.
Make sure that you keep the center point centered. It's easy to move by accident. On the D3200 the center focus point, which is the only 'cross type' one, is a bit more powerful than the others, so when light is poor or focus difficult, keep to that one. This may vary with the user, but I find I often accidentally hit the control due to the way I hold the camera; the [OK] button centers it again.
Remember that depth of field is greater behind the focal point than in front of it (the rough rule of thumb is about 2/3 to 1/3). So if you consider the furthest face as the "behind" limit and the closest face the "in front" limit, you should try to focus between them but with a little bias toward the front.
Of course the closer together in depth the people are, the easier it will be. Also, the further away they all are. Of course you don't want them off in the distance, but you can almost never get multiple subjects in focus if one of them is very close.