Model Design / Appearance
While it has a nice, classic style and is rock solid, the Z850 is not a thrill to look at.
But though it lacks some sparkle, the sturdy all-metal Z850 does feel good in your hand. It’s well balanced, evenly proportioned and has a straightforward classy design that’s obviously the result of much trial and error. We can’t fault Casio for going with a conservative style – we know there are a lot of unpleasant-looking experimental cameras out there – but I wish that they had done something to add a little pizzazz.
Size / Portability
Dimensions on the camera – as expected with a line name that’s a near rhyme with “slim” – are petite. The Z850 measures in at 3.5” (W) x 2.3” (H) x 0.93” (D), which is almost the exact same dimensions of comparable cameras from Sony. However, despite its weight of 4.59 ounces unloaded, the Z850 though feels more substantial than its counterparts.
For carrying around just about anywhere, this camera is ideal. It’s solid enough and seemingly scratch-resistant for all kinds of travel but light enough such that it won’t feel uncomfortable in your pocket.
Handling Ability
The Z850 handles great. It’s well balanced, is smooth to the touch and has enough heft from its all-metal body to feel like a serious device. The zoom lever is responsive and easy to use, and 
while using this camera will be a little unwieldy if your hands aren’t small, that’s the tradeoff for having a camera you can slip into your pocket.
Control Button / Dial Positioning / Size
Button layout and dial positioning seems about as good as you’re going to get on a camera this small. Casio does a good job of putting buttons in places you can get at without the impression of too much clutter. There are maybe a few more buttons than on your average slim camera but it’s not really noticeable because use of space has been optimized. Again, this camera is made for people with small hands, though people with large hands though could do worse on some cramped competing models.
Menus
The Casio menu system has also traditionally been a strong point over the years with easy to read fonts and a great choice of color themes (light and dark greens and browns, orange arrows) that are easy to navigate. Scrolling through the Casio menus feels efficient and you definitely don’t waste time falling into dead ends. The clean steel multi-selector on the back of the camera, while certainly not revolutionary, is easy to use and helps to move through menus quickly. Iconography for the various Best Shot modes are also clear and helpful text explains what each mode does. Casio has licensed the eBay name for its eBay Best Shot mode for the next year and the eBay logo appears on the screen when that mode is selected.
Considering how many features and functions Casio has packed into the Z850, everything is efficiently and clearly organized within the menus.
Ease of Use
Despite packing a range of functions into the small Z850, it’s fairly easy to use even for the novice. Advanced users will like the EX button on the back of the camera that lets you switch into aperture and shutter priority with the touch of one button and via one screen. Beginning users will like the easily selectable Best Shot modes which are featured on the control dial with a BS tag and easily navigable through the color coded, icon-laded menu system. Though there are indeed enough features to keep you crawling through this camera for two days or more, Casio does a good job of arranging them all in a logical and accessible order.
