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 ZS7 and Canon 450D side-by-side from the front, back and top in their relative dimensions. Panasonic ZS7 has external dimensions of 103 x 60 x 33 mm (4.06 x 2.36 x 1.3″) and weighs 218 g (0.48 lb / 7.69 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 ZS7 and the Canon 450D. Panasonic ZS7 is clearly the smaller of the two cameras. Its body is 26mm narrower, 38mm shorter and 29mm thinner than Canon 450D. As you can tell, actually this is not a fair size comparison since Panasonic ZS7 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 ZS7 and Canon 450D.
Now lets look at the top view comparison of Panasonic ZS7 and Canon 450D.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic ZS7 is significantly lighter (306g ) than the Canon 450D 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 450D, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-ZS7 (Lumix DMC-TZ10) 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 Compact Cameras with Weather Sealing Top DSLR Cameras with Weather Sealing
LCD Screen Size and Features
Panasonic ZS7 and Canon 450D's LCD screens have the same diagonal size of 3.00 inches.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.