For new SLR users: What is this little wheel next to the viewfinder (the wheel with the +/1 symbols in this image)?
It is the diopter adjustment.
This personal setting adjusts the eyepiece to your eye, just like a pair of glasses.
- Look through the viewfinder
- Now look at the focus points or the green LED information (“wake up” your camera repeatedly if necessary).
- Turn the diopter all the way up, then all the way down; then find the position where it is sharp – and leave it there.
If you wear glasses, you may be able to set the diopter so you can use the camera without them.
If two people use your camera, you will have to keep adjusting this setting, unless you have the same eyes exactly.