Where the Panasonic ZS50 is designed as a top-of-the-line compact travel zoom, the ZS50 is more consumer-oriented camera, trading a few of the more advanced features for a wink-to-shoot selfie feature.
The ZS45 keeps a compact body and a 1/2.3" sensor, though it downgrades the zoom to 20x instead of 30x. The trade-off? A tilting LCD screen and a wink-to-shoot feature for selfies. Surprisingly though, the ZS45 didn't have to make too many sacrifices to fit those features in a camera that's actually $100 less.
The continuous shooting speed is still a solid 10 fps. Manual modes are still available. Manual focus and RAW shooting are not, however, since the ZS45 is clearly more consumer oriented, it's a smart move by Panasonic--enthusiasts would choose the ZS50 over the selfie features anyway. The options available in the manual settings are slightly downgraded as well, with a more limited ISO range.
Keeping the 1080p HD video, the ZS45 doesn't have the better frame rate of 60 fps that it's big brother has, but 30 fps isn't bad for the price point.
Overall, the ZS45 looks to be a well-rounded consumer camera, with a solid zoom, excellent speed and features for the selfie-lovers of the world. Advanced users will prefer the features ZS50, but as far as a versatile consumer camera, the ZS45 doesn't leave much room for complaint.