It happens when the camera gets closer to objects so I guess, Depth of Field function is turned on.
There is more than one ways to apply DoF in 3dsmax so we have to determine which one is turned on. Plus every renderer might have its own separate DoF settings. It is most likely in the camera settings. You can just turn it off in its settings or set the F-Stop value the the highest possible. High F-Stop values tend to reduce the depth of field, causing the entire scene to be in focus. Another choice is to move the DoF center (It is probably the camera target by default) towards the preferred point of interest. If it is not a target camera, then you should look for a target distance.
There might be DoF settings in render settings dialog, too.
Now if you are certain that the target point is causing the focus problem you can adjust its coordinate towards-away from the camera just by using the viewport navigation controls.

The above selected function moves the target in the direction of the camera, so while checking from the top viewport move the target back and forth until it reaches the point of interest. Don't forget to do this while Auto Key is on and at the right frame. Although this action does not affect your viewpoint, it essentially changes the motion path of the camera target so the overall motion might differ, in some cases, create motion that is not what you been actually looking for. It can be adjusted anyway. Target distance might be adjusted to match throughout the entire camera motion by looking at the motion path of the camera target.
Motion path can be turned on from the Display Panel in the Display Properties section. (A checkbox labeled Motion Path)
Although you can turn on the motion path in the Motion Panel and can edit the control vertices of the path (The keyframes) as a Sub-object of the path. Like editing a spline.

Which renderer are you using? I can help about the Dof Settings accordingly.
Don't forget to set the F-Stop to an acceptable value as it creates the perception of depth and indirectly affect the object scale impression. A wrong focus relationship in the scene may cause the objects to appear smaller.