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 Sony a3500 and Sony A9 side-by-side from the front, back and top in their relative dimensions. Sony a3500 has external dimensions of 128 x 91 x 85 mm (5.04 x 3.58 x 3.35″) and weighs 411 g (0.91 lb / 14.50 oz) (including batteries). Sony A9 has external dimensions of 127 x 96 x 63 mm (5 x 3.78 x 2.48″) and weighs 673 g (1.48 lb / 23.74 oz) (including batteries).
Below you can see the front view size comparison of Sony a3500 and Sony A9. Sony A9 is 1mm narrower and 22mm thinner than Sony a3500 but it is also 5mm taller.
Now lets look at the top view comparison of Sony a3500 and Sony A9.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Sony a3500 is significantly lighter (262g ) than the Sony A9 which may become a big advantage especially on long walking trips.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you have to also take into account the lenses that you will be using with these bodies. Since Sony A9 has a Full frame sensor and Sony a3500 has a smaller APS-C sensor, Sony a3500's lenses for a similar focal length and aperture will generally be lighter and smaller than the Sony A9 lenses.
Thanks to the weather sealed body of A9, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to a3500.
LCD Screen Size and Features
Sony a3500 and Sony A9's LCD screens has the same diagonal size of 3".
On the other hand, Sony A9 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 Sony a3500 has a fixed type screen which provides less flexibility in shooting positions compared to A9.