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 Sony a5100 and YI M1 side-by-side from the front, back and top in their relative dimensions. Sony a5100 has external dimensions of 110 x 63 x 36 mm (4.33 x 2.48 x 1.42″) and weighs 283 g (0.62 lb / 9.98 oz) (including batteries). YI M1 has external dimensions of 114 x 64 x 34 mm (4.49 x 2.52 x 1.34″) and weighs 350 (including batteries).
Below you can see the front-view size comparison of the Sony a5100 and the YI M1. Sony a5100 is 4mm narrower and 1mm shorter than YI M1 but it is also 2mm thicker.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
YI M1 is 283g lighter than the Sony a5100 but we don't think this will make a significant difference.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you also have to take into account the lenses that you will be using with these bodies. Since Sony a5100 has an APS-C sized sensor and YI M1 has a smaller Four Thirds sensor, YI M1's lenses for a similar focal length and aperture will generally be lighter and smaller than the Sony a5100 lenses.
Weather Sealing
Unfortunately neither the Sony Alpha a5100 nor YI M1 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 Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Sony a5100 and YI M1's LCD screens have the same diagonal size of 3.00 inches.
On the other hand, Sony a5100 features a
Tilting screen where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels whereas the YI M1 has a fixed type screen which provides less flexibility in shooting positions compared to a5100.