02-13-2009, 11:10 AM
What camera are you using, or more to the point, does it have an aperture adjustment? If it does, the higher the number, the smaller the lens opening will be. A small f-stop, 16 or even 32 if it is available will give you a better "depth of field." Large f-stops like a 2 will give you a smaller depth of field. Depth of field will determine how much of the picture is in focus. A picture of a piece of rolling stock on a plain back ground can be done with a large lens opening because you are going to focus on the subject only. If you are shooting a scene on a diorama or layout where you have objects up close, others in the back ground, and still others in between, you need to use a smaller aperture to get it all in focus. Of course a smaller aperture means either a longer exposure or a the use of flood light to allow enough light for everything.