Camera dimmensions different than render dimmensions I have a camera in my scene which is placed at the ideal position. With the button  I look through it and with the settings for camera I calibrated the dimmensions of the camera viewport (the orange-border looks great). But If I'm going to render it, the aspect radio seems to change (see the pictures).

How can I solve this?
You appear to have the Aspect Ratio set to 4/3 as shown in the below image :



This changes the ratio of the camera. You should generally leave the Aspect Ratio to its default of 1.000/1.000 for 'square' pixels and use the Resolution to set the dimensions of rendered image.