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 Canon 40D and Panasonic FZ300 side-by-side from the front, back and top in their relative dimensions. Canon 40D has external dimensions of 146 x 108 x 74 mm (5.75 x 4.25 x 2.91″) and weighs 822 g (1.81 lb / 29.00 oz) (including batteries). Panasonic FZ300 has external dimensions of 132 x 92 x 117 mm (5.2 x 3.62 x 4.61″) and weighs 691 g (including batteries).
Below you can see the front-view size comparison of the Canon 40D and the Panasonic FZ300. Panasonic FZ300 is 14mm narrower and 16mm shorter than Canon 40D but it is also 43mm thicker. As you can tell, actually this is not a fair size comparison since Panasonic FZ300 has a built-in lens but Canon 40D doesn't. Once you put a lens on 40D, its thickness will increase significantly.
Here is the back view size comparison of the Canon 40D and Panasonic FZ300.
Now lets look at the top view comparison of Canon 40D and Panasonic FZ300.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic FZ300 is significantly lighter (131g ) than the Canon 40D 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 40D, the total kit will weigh much higher.
Weather Sealing
Both the 40D and the FZ300 have weather sealings in their bodies, making them resistant to water and dust.
LCD Screen Size and Features
Canon 40D and Panasonic FZ300's LCD screens have the same diagonal size of 3.00 inches.
On the other hand, Panasonic FZ300 sports a
Fully Articulated screen which you can change the angle and position of the screen almost freely, making it possible to shoot from waist or over-the-head levels, and especially very useful for shooting selfies and video. Canon 40D's LCD screen is a fixed type which provides almost no flexibility in shooting positions compared to FZ300.