- k550 has small camera module so it give worse picture in low light than k750. It's technical fact.
+ but k550 has scene mode and metering mode which k750 didn't. That's pros about k550 camera to (unmodified) k750.
+ k550 is faster than k750 is true too, just test by zooming picture :)
+ besides, k550 also support wma and hi-res video (320x240 at least) too. which k750 didn't
... and AFAIK, k550 didn't has flash support, at least for generic sw/fw





