Focus question

Hello all..

I have a question, that may sound silly, but as a beginner, these simple concepts are not always EASY to grasp...

When taking shots with my xti, the focus points have to be selected....so depending on the one chosen, will determine what aspect of the shot is in crisp focus....BUt what if i want the ENTIRE shot in focus??? i NEVER want the camera to choose the focus point, bc it will probably NEVER be right, but i can't, for the life of me, get a shot where EVERYTING is in crisp focus....

Help??thx

What you are trying to achieve, is a wider depth of field (DOF). The DOF is an aspect that the photographer (ie., you) control for creative effect. A shallow DOF will allow you to emphasize the subject, while throwing other portions of the image out of focus. A wider DOF will help you capture more of an image within the focal range that is in sharper focus.

The depth of field is a function of both the aperture and the focal length of your lens. A third factor is your subject distance. A wider aperture combined with a longer focal length will shrink your DOF; a smaller aperture combined with a shorter focal length will give you a wider DOF.

Experiment with these settings (the easiest to adjust is your aperture setting) to see how it affects your images to make them look more interesting. In addition, you can check out the website below to get a better understanding of how to combine these factors along with your subject distance (ie., distance from the subject to the film plane of your camera) to truly appreciate how DOF can be used in your photos.

Here's the website:
http://www.dofmaster.c​om/dofjs.html

Have fun.

As the response mentioned, to get more of the scene in focus you need to stop down the aperture.....that is, you must select a smaller aperture (higher number) in Av or M modes.

Now, a smaller aperture will not only provide more DOF, it will also let in less light as you are making the hole in the lens smaller. So in order to compensate the camera will also need to use a longer shutter open time (slower shutter speed) to expose the scene. If you go too far the slow shutter speed will cause motion blur from the subjects moving or from the photographer moving.

You can solve photographer moving issues with a tripod, and you can solve both by increasing the ISO setting to make the sensor more sensitive to light. This lets you speed the shutter back up to where there are no blur problems.

You would benefit greatly from picking up a good book on the basics of photography. Bryan Peterson's "Understanding Exposure" will be a good one to introduce you to the concepts of f-stop, shutter speed, and ISO, including how they relate to each other, and how each of them affects what the photograph will look like.

Good luck!