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 SX510 HS and Canon SX170 IS side-by-side from the front, back and top in their relative dimensions. Canon SX510 HS has external dimensions of 104 x 70 x 80 mm (4.09 x 2.76 x 3.15″) and weighs 349 g (0.77 lb / 12.31 oz) (including batteries). Canon SX170 IS has external dimensions of 108 x 71 x 44 mm (4.25 x 2.8 x 1.73″) and weighs 251 g (0.55 lb / 8.85 oz) (including batteries).
Below you can see the front-view size comparison of the Canon SX510 HS and the Canon SX170 IS. Canon SX510 HS is 4mm narrower and 1mm shorter than Canon SX170 IS but it is also 36mm thicker.
Now lets look at the top view comparison of Canon SX510 HS and Canon SX170 IS.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Canon SX170 IS is significantly lighter (98g ) than the Canon SX510 HS which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Canon PowerShot SX510 HS nor Canon PowerShot SX170 IS 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
Canon SX510 HS and Canon SX170 IS's LCD screens have the same diagonal size of 3.00 inches.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.