Beginner Locked focus

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brian andrew

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Hi
You will understand why i am in the Beginners section :).
got a d3000 if i zoom into capture a image & i refocus, and then zoom out to take picture how do i lock that in so that the everything is in focus.

Sorry cannot word it any better.
 
brian andrew said:
Hi
You will understand why i am in the Beginners section :).
got a d3000 if i zoom into capture a image & i refocus, and then zoom out to take picture how do i lock that in so that the everything is in focus.

Sorry cannot word it any better.
Click to expand...
You would have to focus again at the new focal length

Or have the camera set on continuous auto focus
 
Seems to me your trying to focus twice for the same shot. I wonder what f stop your using you don't say but a rough starting guide would be something like f8 for a reasonable depth of field. for a shallow depth of field f2.8 and greater DOF you need to work up from there . DOF is amount in focus infront and behind subject

link
www.nfi.edu

Depth of Field - Everything You Need To Know - NFI

What is Depth of Field? Depth of field is one of the essential concepts in photography. The depth of field in a photo refers to the distance between the closest and farthest objects that appears acceptably sharp. Depth of field differs based on camera type, aperture, and focusing distance. In...
www.nfi.edu www.nfi.edu

hope this helps
 
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You can't always assume that the lens will remain in focus, so its always best to focus at the focal length you are using. Unless you are working on very wide apertures where the plane of focus is very thin... Same is true with 'focus and recompose' which is less of a problem now cameras have a lot more focus points.
 
Focus , flick the lens to manual , zoom in or out and take the shot
 
brian andrew said:
Hi
You will understand why i am in the Beginners section :).
got a d3000 if i zoom into capture a image & i refocus, and then zoom out to take picture how do i lock that in so that the everything is in focus.

Sorry cannot word it any better.
Click to expand...

As above, this isn't really a good way to do things Brian. I think it's best to frame the shot / set the focal length and then focus and take the shot. Doing it the way you're trying might well give good enough results when looking at a whole picture but if you look closely you may well see issues plus of course depending on how you've got the camera set up if you keep the shutter half pressed when zooming out the exposure could be affected. Metering and focusing with the framing and zoom length you want seems to be much the best way forward, IMO.
 
Still camera lenses are typically varifocal. They require you to refocus every time you zoom, or the picture won't be optimally sharp. Good depth of field might result in acceptable sharpness, but not optimal.

Cine lenses are parfocal - focus stays the same as the lens is zoomed.

Parfocal lenses are highly desirable for video because you can zoom while shooting without the camera 'hunting' to keep the image in focus - which is not an issue in still photography, especially with autofocus. However, they are astonishingly expensive, compared to varifocals.

In short, you just have to focus twice for the best result.
 
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