Size and weight are big decision factors when you are trying to find the ideal camera for your needs.
In this section, we are going to illustrate the Panasonic ZR3 and Nikon P340 side-by-side from the front, back and top in their relative dimensions. Panasonic ZR3 has external dimensions of 98 x 55 x 26 mm (3.86 x 2.17 x 1.02″) and weighs 159 g (0.35 lb / 5.61 oz) (including batteries). Nikon P340 has external dimensions of 103 x 58 x 32 mm (4.06 x 2.28 x 1.26″) and weighs 194 g (0.43 lb / 6.84 oz) (including batteries).
Below you can see the front-view size comparison of the Panasonic ZR3 and the Nikon P340. Panasonic ZR3 is clearly the smaller of the two cameras. Its body is 5mm narrower, 3mm shorter and 6mm thinner than Nikon P340.
Here is the back view size comparison of the Panasonic ZR3 and Nikon P340.
Now lets look at the top view comparison of Panasonic ZR3 and Nikon P340.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic ZR3 is significantly lighter (35g ) than the Nikon P340 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-ZR3 (Lumix DMC-ZX3) nor Nikon Coolpix P340 provides any type of weather sealing in their bodies, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Nikon P340's 3.00" LCD screen is slightly larger than Panasonic ZR3's 2.7 screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.