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 Panasonic ZS100 and Nikon S3500 side-by-side from the front, back and top in their relative dimensions. Panasonic ZS100 has external dimensions of 111 x 65 x 44 mm (4.37 x 2.56 x 1.73″) and weighs 312 g (0.69 lb / 11.01 oz) (including batteries). Nikon S3500 has external dimensions of and weighs 129 g (including batteries).
Below you can see the front-view size comparison of the Panasonic ZS100 and the Nikon S3500. Nikon S3500 is clearly the smaller of the two cameras. Its body is 14mm narrower, 7mm shorter and 23mm thinner than Panasonic ZS100.
Here is the back view size comparison of the Panasonic ZS100 and Nikon S3500.
Now lets look at the top view comparison of Panasonic ZS100 and Nikon S3500.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Nikon S3500 is significantly lighter (183g ) than the Panasonic ZS100 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-ZS100 (Lumix DMC-TZ100) nor Nikon Coolpix S3500 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 Compact Cameras with Weather Sealing
LCD Screen Size and Features
Panasonic ZS100's 3.00" LCD screen is slightly larger than Nikon S3500's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.