If you switch to tactical view while looking through binoculars or scope, you will be zoomed into the player's head and unable to zoom out.
You have to unequip binoculars before using tactical view. This makes it much more tedious to command subordinates optimally while spotting targets from a distance.
I uploaded a video showing the difference: http://youtu.be/krSw1rp3cPM
Make sure the difficulty setting allows 3rd person and tactical view.
Very unrealitic and unfair with 3rd person, it's a sim, stay in 1st or play another game...
Hmmmm. Sorry if I'm not cool & hardcore enough to stay in 1st person because 'it's a sim'. It can also be a game or casual toy, depending on the size of stick lodged in your rectum. If you're so hardcore maybe you should go play paintball, so no software features hinder your experience.
If you're playing with AI only and want to position your squad, it helps to use tactical view so you don't have to walk to every spot you want to place your team members. I don't think the enemy AI will mind if it's not 'fair'. Plus it provides another way to view the awesomely detailed models.
If you're playing PVP then yeah, disable 3rd person via difficulty settings.