Cum pot face zoom pentru o anumita distanta focala?

Here’s the experiment you can run:
1.  Set up a scene on a table or find something in your surroundings that duplicates the distances listed below.
    Set your camera on a steady object or make sure you hold it in the same spot for this experiment.
    Set an object 2′/.6m in front of your camera.
    Set another object 2′/.6m beyond that object.
    Set one last object 4′/1.2m beyond the second object. These measurements need not be exact.
2.  Set your camera to Aperture Priority (it’s the little A or Av item on the control dial, likely on top).
3.  Zoom in to 50mm or as close as you can get to that focal length. If you are using a point and shoot, zoom in half way from the nearest to the farthest zooms.
4.  Focus on the first object but keep the other two objects in the field of view. Move the objects side to side as needed, but try not to move them front to back.
5.  Lock the focus of your camera by changing it to manual. This helps your camera to not pick a new focus point during this experiment which can ruin things.
6.  Set your ISO to 400 for a middle of the road setting. This is not critical to this experiment.
7.  Set the aperture setting to the smallest number it can achieve. This is usually done by spinning one of the control wheels on your camera. Your lowest aperture may be f/2.8 0r f/4 or f/5.6. It’s not too important right now what this number is.
8.  Take a photo.

Va fi destul de greu sa observi modificari ale profunzimii cu aparatul tau ,poate doar daca te duci cu zoomul pana la maxim si focalizezi pe un obiect cat mai aproape de distanta minima la care poate sa focalizeze obiectivul.