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 Fujifilm X100 and Fujifilm X-Pro1 side-by-side from the front, back and top in their relative dimensions. Fujifilm X100 has external dimensions of 126 x 75 x 54 mm (4.96 x 2.95 x 2.13″) and weighs 445 g (0.98 lb / 15.70 oz) (including batteries). Fujifilm X-Pro1 has external dimensions of 140 x 82 x 43 mm (5.51 x 3.23 x 1.69″) and weighs 450 g (0.99 lb / 15.87 oz) (including batteries).
Below you can see the front view size comparison of Fujifilm X100 and Fujifilm X-Pro1. Fujifilm X100 is 14mm narrower and 7mm shorter than Fujifilm X-Pro1 but it is also 11mm thicker. As you can tell, actually this is not a fair size comparison since Fujifilm X100 has a built-in lens but Fujifilm X-Pro1 doesn't. Once you put a lens on X-Pro1, its thickness will increase significantly.
Here is the back view size comparison of Fujifilm X100 and Fujifilm X-Pro1.
Now lets look at the top view comparison of Fujifilm X100 and Fujifilm X-Pro1.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Fujifilm X100 is 5g lighter than the Fujifilm X-Pro1 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 X-Pro1, the total kit will weigh much higher.
Unfortunately neither Fujifilm FinePix X100 nor Fujifilm X-Pro1 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 Compact Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Fujifilm X-Pro1's 3" LCD screen is slightly larger than Fujifilm X100's 2.8" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.