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 A2100 IS and Canon 5D side-by-side from the front, back and top in their relative dimensions. Canon A2100 IS has external dimensions of 102 x 64 x 32 mm (4.02 x 2.52 x 1.26″) and weighs 185 g (0.41 lb / 6.53 oz) (including batteries). Canon 5D has external dimensions of 152 x 113 x 75 mm (5.98 x 4.45 x 2.95″) and weighs 895 g (1.97 lb / 31.57 oz) (including batteries).
Below you can see the front-view size comparison of the Canon A2100 IS and the Canon 5D. Canon A2100 IS is clearly the smaller of the two cameras. Its body is 50mm narrower, 49mm shorter and 43mm thinner than Canon 5D. As you can tell, actually this is not a fair size comparison since Canon A2100 IS has a built-in lens but Canon 5D doesn't. Once you put a lens on 5D, its thickness will increase significantly.
Here is the back view size comparison of the Canon A2100 IS and Canon 5D.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Canon A2100 IS is significantly lighter (710g ) than the Canon 5D 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 5D, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the 5D, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the A2100 IS.
LCD Screen Size and Features
Canon A2100 IS's 3.00" LCD screen is slightly larger than Canon 5D's 2.5" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.