Though the buttons on the LZ5 and LZ3 are smaller than the ones on many other compact cameras, they are placed well and spread far enough apart. We expect that users with large fingers or with poor hand mobility will find the LZ5 and LZ3 as easy to use as other popular compact cameras. 
The layout of the camera makes it easy to stay in shooting position, since all the feedback for adjustments come on the LCD, and the controls are pretty natural to hit with the right thumb.
Menus
The LZ5 and LZ3 subdivide menus into three sections: shooting, set-up, and playback. Each section has three screens worth of settings, and the user must scroll through the list to get to setting. We didn't find a way to “jump” to the middle of a section. The shooting and playback menus only appear when the LZ5 and LZ3 are in the respective mode, but set-up is available all the time. There is a tabbed interface to switch quickly between set-up and the other sections.
The menus appear in a large, plain sanserif font which was readable on both cameras. Panasonic does a little color coding: the shooting menu has a red heading, playback has a green one, and set-up is gray.
The shooting menu has standard controls for a compact: White balance, ISO, Aspect ratio, Picture size, Quality, Audio recording, Autofocus mode, Autofocus assist lamp, Slow shutter speed limit, Digital Zoom, Color effects and Picture Adjustment. Slow shutter speed limit is a useful feature. It prevents the LZ5 or LZ3 from automatically setting a shutter speed below a given speed. 1/8 of a second is the default, but it can be set for exposures as long as 1 second. Color effects include black-and-white and sepia, as well as warm-tone and cool-tone. Picture adjustment seems to alter saturation.
The menus mainly appear on a white background, except for White balance, Color effects, and Picture adjustment, which are superimposed over the live view, so the user can see the effect of the adjustment prior to rendering the selection.
Set-up covers typical stuff: battery type, the date and time, LCD brightness, last shot review, beeps, power savings, frame numbering, a reset control, USB mode, video mode, the way scene modes show up (whether the camera defaults to the last scene mode used or displays a menu of all of them), and the language used on the display.
The Playback menu covers Slide show options, choosing Favorite images, image Rotation, direct printing through the DPOF standard, image Protect, Audio Dubbing, Resizing images (to smaller sizes), Trimming (cropping), Copying images to internal memory, and Formatting memory cards.
The menu options on the LZ5 and LZ3 are standard for compact digital cameras – there's nothing tricky for experienced users. The shooting mode menu shows the most important stuff first – white balance, ISO, and image size/quality.
Ease of Use
The LZ5 and LZ3 have a simple and straightforward interface. The controls are well placed and easy to find. Other entry level cameras, notably the Kodak EasyShare line, offer more help options, but for users who have a basic understanding of the settings, the interface is fine. There is even a simple mode, which sets everything for the user and even hides all the options.
On the other hand, the LZ5 and LZ3 do not allow much manual control. Users who want to set a particular shutter speed or aperture are out of luck. There is an exposure compensation control which allows 2 stops of adjustment above and below the meter reading. The LZ5 and LZ3 can set custom white balances as well.
The LZ5 and LZ3 can show live histograms while shooting, helping users to attain a proper exposure; however, the histogram is small, and taller than it is wide, making it tough to use. Part of the problem is the low resolution of the LCD displays.
The ergonomics of simple tasks like changing batteries, swapping memory cards, and plugging in cables are all good – there aren't any awkward placements that make it hard to do those quickly.