If you walked into a store and saw Panasonic's Lumix DMC-ZS8 and its Lumix DMC-ZS10 next to each other, you might not immediately see the differences, let alone $100 worth of them. Even after picking them up, you might notice only that the ZS10 has a GPS receiver and a touch screen. And a stereo mic. Oh, and look, it records full HD video in AVCHD with a one-touch record button.
But if none of that matters to you, then maybe the more hidden differences will, like the fact that the ZS10's screen is twice the resolution of the ZS8's and that it uses a high-speed sensor and better processor for faster shooting performance or, more specifically, faster full-resolution burst shooting and 3D photos.
So, though the ZS8 might not look like it's missing $100 in features, it is. Potentially more, depending on how much you value any of the ZS10's extra features or faster continuous shooting. Panasonic really gives you a lot more in the ZS10 for that $100 difference, making it a better value than the ZS8, even at the higher price.
Read the full review of the Panasonic Lumix DMC-ZS8
Read the full review of the Panasonic Lumix DMC-ZS10
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However, if all you're after is a speedy camera with a long lens in a pocketable body, one that takes good pictures and decent 720p HD movie clips and has semimanual and manual shooting modes, then, yes, save yourself $100 and get the ZS8. On second thought, you might be able to save yourself even more.
The ZS8 doesn't differ all that much from its predecessor, the DMC-ZS5; the ZS8's wider, longer lens is the biggest difference, along with an increase in megapixels and a slightly larger LCD. The larger display is nice, but the other two changes don't do anything to improve photo quality. And since it's on its way out, the ZS5 can be found for less than $200.