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 Samsung NX100 and Canon A3400 IS side-by-side from the front, back and top in their relative dimensions. Samsung NX100 has external dimensions of 120 x 71 x 35 mm (4.72 x 2.8 x 1.38″) and weighs 282 g (0.62 lb / 9.95 oz) (including batteries). Canon A3400 IS has external dimensions of 94 x 56 x 21 mm (3.7 x 2.2 x 0.83″) and weighs 126 g (0.28 lb / 4.44 oz) (including batteries).
Below you can see the front view size comparison of Samsung NX100 and Canon A3400 IS. Canon A3400 IS is clearly the smaller of the two cameras. Its body is 26mm narrower, 15mm shorter and 14mm thinner than Samsung NX100. As you can tell, actually this is not a fair size comparison since Canon A3400 IS has a built-in lens but Samsung NX100 doesn't. Once you put a lens on NX100, its thickness will increase significantly.
Now lets look at the top view comparison of Samsung NX100 and Canon A3400 IS.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Canon A3400 IS is significantly lighter (156g ) than the Samsung NX100 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 NX100, the total kit will weigh much higher.
Unfortunately neither Samsung NX100 nor Canon PowerShot A3400 IS 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 Mirrorless Cameras with Weather Sealing Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Samsung NX100 and Canon A3400 IS's LCD screens has the same diagonal size of 3".
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.