Focus Distance

[Andy]

How does a person know if his or her lens is too close to the main subject to be focused on? Is it possible to get a sharp focus in the view-finder on an object but still be too close and get an out-of-focus print? What are some of the basic rules for "close-up" shooting?

[Richard Knight]

If you are using an SLR, the image in the viewfinder will mirror the focus on the negative. If the image is out of focus in the viewfinder, then it will also be on the negative.
The key to focus in macro photography is depth of field (the amount of the image in relation to the foreground/background that is in focus). This is where a DOF preview button on your camera is invaluable. The DOF button will cause the lens to stop down to the adjusted aperture so you can see the amount of the image that is in focus. The major problem in using DOF preview is that at the smaller apertures (where the DOF is largest), the viewfinder image can be very dark. I try to concentrate on sharp areas of the image with high contrast(maybe the edge of a flower petal or leaf against a lighter or darker background in the area I want in focus). This helps me determine whether all the subjects at this distance from the lens are in focus