[quote=@thewizardguy]
[@TheWindel]
So a lead bullet and a pillow would cost the same amount of energy to create? Considering the lead bullet has far more mass, but the pillow has far more volume.
[/quote]

More or less like that.

However, the eyes still follow the minimum logic. So, if you attempted to create a bullet flying at lethal speeds, it would cost far less than a pillow flying at lethal speeds, since you'd need far more contrived conditions (not only would you need more energy, but also to create a pillow that doesn't get destroyed by the forces involved) to have the second one work.

Ultimately, the Silver Eyes are much better to create things that your character is knowledgeable of/intimate to, or at least, something that he can get a decent mental image of. That's one of the reasons why Henry's black holes pale in comparison to what he saw Juno do before. Aside from the fact that she's the physical embodiment of space and gravity, there's the fact that he doesn't know how gravity works.