Page 6. Version 1.1, Page 1, ©2001 by Dale Cotton, all rights reserved.
When it comes down to one's having chosen a promising position, angle-of-view, and focal length, there still remains those last minute adjustments that can make or break a shot. A little left or right; a little up or down. The obvious solution is to switch to a wider focal length, include more of the scene, then make your final crop in the darkroom (analogue or digital). Two problems. First, the more you have to crop your film frame, the less detail is left for enlargement. Second, this option isn't even open to those who shoot transparencies, unless the sole use is for printing. Better to get it right in the field.
But even then there is always the issue of whether the composition you are visualising happens to match the aspect ratio of your camera's frame. 35mm film frames are roughly 1" tall by 1.5" wide - a two to three aspect ratio. 645 is roughly three to four. And of course 6x6 is one to one. Two to three, being slightly panoramic, happens to be a good match for my compositional instincts. But in the case of one picture in five or so I want a different aspect ratio and know that part of the frame will be wasted. All the more reason to:
Get as close to your final crop as possible before you press the shutter release.