Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate Pentax RZ10 and Canon 450D side-by-side from the front, back and top in their relative dimensions. Pentax RZ10 has external dimensions of 97 x 61 x 33 mm (3.82 x 2.4 x 1.3″) and weighs 178 g (0.39 lb / 6.28 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 Pentax RZ10 and Canon 450D. Pentax RZ10 is clearly the smaller of the two cameras. Its body is 32mm narrower, 37mm shorter and 29mm thinner than Canon 450D. As you can tell, actually this is not a fair size comparison since Pentax RZ10 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 Pentax RZ10 and Canon 450D.
Now lets look at the top view comparison of Pentax RZ10 and Canon 450D.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Pentax RZ10 is significantly lighter (346g ) 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.
With its weather sealed body, we believe that RZ10 has a big advantage over 450D which doesn't provide any kind of environmental sealing.
LCD Screen Size and Features
Canon 450D's 3" LCD screen is slightly larger than Pentax RZ10's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.