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 SX420 IS and Canon SX400 IS side-by-side from the front, back and top in their relative dimensions. Canon SX420 IS has external dimensions of 104 x 69 x 85 mm (4.09 x 2.72 x 3.35″) and weighs 325 g (0.72 lb / 11.46 oz) (including batteries). Canon SX400 IS has external dimensions of 104 x 69 x 80 mm (4.09 x 2.72 x 3.15″) and weighs 313 g (0.69 lb / 11.04 oz) (including batteries).
Below you can see the front-view size comparison of the Canon SX420 IS and the Canon SX400 IS. Canon SX420 IS has the same height and width with Canon SX400 IS. On the other hand, with a thickness of 85mm, it is 5mm thicker.
Here is the back view size comparison of the Canon SX420 IS and Canon SX400 IS.
Now lets look at the top view comparison of Canon SX420 IS and Canon SX400 IS.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Canon SX400 IS is 12g lighter than the Canon SX420 IS but we don't think this will make a significant difference.
Weather Sealing
Unfortunately neither the Canon PowerShot SX420 IS nor Canon PowerShot SX400 IS 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 Compact Cameras with Weather Sealing
LCD Screen Size and Features
Canon SX420 IS and Canon SX400 IS'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.