[Ron Wood]

You get a "fish-eye" effect with macro/closeup settings on a point and shoot camera. It allows the software to sharply focus at close range but the lens introduces spherical aberration because of the curvature of the lens. This usually can only be corrected by a seperate close-up lens that corrects for this condition. To get sharp photos without introducing a "curve" it is best to use a high resolution setting and shoot from a bit longer distance using the zoom function to get a close up effect. Also shooting at a high resolution then cropping the photo to the portion that you want to illustrate helps. Macro settings are only useful for a very close up photo of a small area, not the entire gun (for instance, you could us the macro setting to take a sharp photo of the rampant colt logo on the grip). It also is much less apparent for not-linear objects (you don't notice the bend).
Some higher end cameras have on board photo editing capabiliies that folks that know how to use them (not me) can manipulate fish-eye and correct for it.
Ron