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 Panasonic GF7 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). Panasonic GF7 has external dimensions of 107 x 65 x 33 mm (4.21 x 2.56 x 1.3″) and weighs 266 g (0.59 lb / 9.38 oz) (including batteries).
Below you can see the front-view size comparison of the Panasonic ZR3 and the Panasonic GF7. Panasonic ZR3 is clearly the smaller of the two cameras. Its body is 9mm narrower, 10mm shorter and 7mm thinner than Panasonic GF7. As you can tell, actually this is not a fair size comparison since Panasonic ZR3 has a built-in lens but Panasonic GF7 doesn't. Once you put a lens on GF7, its thickness will increase significantly.
Here is the back view size comparison of the Panasonic ZR3 and Panasonic GF7.
Now lets look at the top view comparison of Panasonic ZR3 and Panasonic GF7.
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 (107g ) than the Panasonic GF7 which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on GF7, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-ZR3 (Lumix DMC-ZX3) nor Panasonic Lumix DMC-GF7 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 Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Panasonic GF7's 3.00" LCD screen is slightly larger than Panasonic ZR3's 2.7 screen.
In addition to the size advantage, Panasonic GF7 LCD screen also has a
Tilting feature where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels. On the other hand, Panasonic ZR3 has a fixed type screen which provides less flexibility in shooting positions compared to GF7.