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 FZ100 and Canon 450D side-by-side from the front, back and top in their relative dimensions. Panasonic FZ100 has external dimensions of 124 x 82 x 92 mm (4.88 x 3.23 x 3.62″) and weighs 540 g (1.19 lb / 19.05 oz) (including batteries). Canon 450D has external dimensions of 129 x 98 x 62 mm (5.08 x 3.86 x 2.44″) and weighs 524 g (1.16 lb / 18.48 oz) (including batteries).
Below you can see the front-view size comparison of the Panasonic FZ100 and the Canon 450D. Panasonic FZ100 is 5mm narrower and 16mm shorter than Canon 450D but it is also 30mm thicker. As you can tell, actually this is not a fair size comparison since Panasonic FZ100 has a built-in lens but Canon 450D doesn't. Once you put a lens on 450D, its thickness will increase significantly.
Here is the back view size comparison of the Panasonic FZ100 and Canon 450D.
Now lets look at the top view comparison of Panasonic FZ100 and Canon 450D.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Canon 450D is 16g lighter than the Panasonic FZ100 but we don't think this will make a significant difference.
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 450D, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-FZ100 nor Canon EOS 450D (EOS Rebel XSi / EOS Kiss X2) 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 Bridge Cameras with Weather Sealing Top DSLR Cameras with Weather Sealing
LCD Screen Size and Features
Panasonic FZ100 and Canon 450D's LCD screens have the same diagonal size of 3.00 inches.
On the other hand, Panasonic FZ100 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 450D's LCD screen is a fixed type which provides almost no flexibility in shooting positions compared to FZ100.