For work I use my laptop to give presentations on a projector. The projector only has a VGA cable and my laptop doesn’t have a VGA slot, so I use an HDMI-VGA converter. But when I do so, the image on my screen only shows up as a relatively small square, rather than filling up the entire projector screen.
Anything I can do?
Usually on laptops one of the Function keys has a label to adjust screen resolution for an external projector. It will have a small icon, frequently blue colored, showing a little monitor
If your laptop is trying to display the same thing on both its own screen and the projector, it may have arrived at a compromise situation that works, but isn’t ideal for either.
If your laptop is Windows 7 or higher, try holding the Windows key and pressing P - this will bring up a dialog that gives you the choice to ‘extend’ - so the projector acts like a second monitor - you can drag windows across to it and maximise them there.
That ought to allow the machine to choose the optimal resolution for each screen independently of the other.
Also check that the projector isn’t zoomed out (either physically by a lens ring, or digitally using the controls or remote).
Yes, typically if you are mirroring/duplicating the screen you get the lowest resolution (say, older projector is 1024x768). If your screen is better than this (most new ones are) the leftover area will be black.
There are several good suggestions above - create a dual-screen situation, redefine you local screen to projector’s resolution, etc.