i have an 11" air and i hook it up to my 25" HP hd mon with no problems. I do so via dvi since i only have one hdmi slot and i use it for my xbox/ps3
now, i notice that the images on my external mon arent as sharp as it looks on my air... is it because i am using a no name brand adapter to hook it up to my monitor?
i have a sony vaio laptop that's older, and via vga connection, it looks way sharper than my macbook air on the same external monitor
i know theres nothing wrong with the monitor... is there an app that i should dl for the air, or an optimal resolution that i should set the air to?
If its digital, no it doesn't matter how cheap the adapter is. Digital means it works or it doesn't.
There are many HDTVs which do not support their native resolutions via HDMI. Not sure why. I think its something about assuming you're connecting to a DVD player or something. In particular, I've had lots of trouble with older Samsung HDTVs. My Vizio HDTV also refuses to connect via HDMI at its native resolution. I have to use VGA to my HDTV to get native resolution, then it looks fine.
I'd check the manual for the monitor and see what they support via what interface. Then use the interface that supports the monitors native resolution. Anything that doesn't exactly match its native resolution will end up looking fuzzy or blocky or in some way not as good.
You can also check display preferences and see if a non-optimal resolution has been picked.