Disputes about the size of a logo are the most tedious conversations you can possibly have. Personally I'm glad when a brand has a fixed rule about logo size; it eliminates the debate.
But no one seems to have a fixed rule about packshots.
The general principle at many companies seems to be 'just make it as big as possible'.
In the above ad, you can almost hear the Client cursing the limitations of the media space, for unfairly constraining the size at which his product can be displayed.
Of course, some find a clever way around that.
Well, at least it wasn't horizontal.
Actually there's a surprising degree of variation in pack sizes. Apple packshots, for example, vary from subtle sizes like this:
To whoppers like this:
This one I reckon is the biggest. It's an Armani ad from 1983. Shame about those little bits of black space around the shoulders of the bottle. Otherwise it would have been perfect!
In terms of what the ideal packshot size is, I honestly don't think it's that hard to work out. The principles are the same as with any art direction (*disclaimer: I'm not an art director).
You simply need to have a clear vision of the order in which you want a consumer to view the different elements of your ad.
In the example below, it was obviously felt that consumers should see LeBron James first, since he's been made the biggest element. (Correct decision, I'd say. It's LeBron that is going to hook people in).
Next, the art director wanted people to read the headline. So that's the second biggest element. Then the shoes (third biggest) and finally the tagline.
Art directors: is this what you actually do, or am I just making it up?