4x4,
If your buddy wants to log time as flight by reference to instruments, he must use a view limiting device like a hood or foggles. The only time you can log is the time in which he is flying under the foggles. However, he is still the PIC because he is the sole manipulator of the controls. Since you are not flying by reference to instruments, and looking outside for traffic and terrain avoidance as a good safety pilot should be, you can not log any instrument time. I had a discussion with our POI on the subject. I have heard so many different interpretations of this rule that I wanted some clarity and this is what he basically said:
When acting as a safety pilot, you will only be able to log the total time, and as for PIC it will be however long you are the sole manipulator of the controls. Therefore, you might get .2 in a 1 hour flight if your buddy is really slow in putting his hood on.
Safety pilot time is pretty useless in my book because you're not getting much out of it. I usually don't log it but will gladly go up with anybody that needs an extra set of eyes and sign their logbook. The only time I log it is when I'm in a multi because that's the time that's hard to get. If you're working through your ratings with hopes of becomming a professional in the industry those four or five hours of safety pilot time can easily be made up in a good day of flight instruction (and that's PIC no matter what!).