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 Canon 400D and Sony HX1 side-by-side from the front, back and top in their relative dimensions. Canon 400D has external dimensions of 127 x 94 x 65 mm (5 x 3.7 x 2.56″) and weighs 556 g (1.23 lb / 19.61 oz) (including batteries). Sony HX1 has external dimensions of 115 x 83 x 92 mm (4.53 x 3.27 x 3.62″) and weighs 544 g (1.20 lb / 19.19 oz) (including batteries).
Below you can see the front view size comparison of Canon 400D and Sony HX1. Sony HX1 is 12mm narrower and 11mm shorter than Canon 400D but it is also 27mm thicker. As you can tell, actually this is not a fair size comparison since Sony HX1 has a built-in lens but Canon 400D doesn't. Once you put a lens on 400D, its thickness will increase significantly.
Now lets look at the top view comparison of Canon 400D and Sony HX1.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Sony HX1 is 12g lighter than the Canon 400D 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 400D, the total kit will weigh much higher.
Unfortunately neither Canon EOS 400D (EOS Digital Rebel XTi / EOS Kiss Digital X) nor Sony Cyber-shot DSC-HX1 provides any type of weather sealing in their body, 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 DSLR Cameras with Weather Sealing Top Bridge Cameras with Weather Sealing
LCD Screen Size and Features
Sony HX1's 3" LCD screen is slightly larger than Canon 400D's 2.5" screen.
In addition to the size advantage, Sony HX1 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, Canon 400D has a fixed type screen which provides less flexibility in shooting positions compared to HX1.