A key difference between the EOS 100D and EOS 700D is the type of screen they feature. Though the physical dimensions of the screens measure 3inch in size and offer the same 1040k-dot resolution, the 100D's is fixed compared to the 700D's vari-angle design.

Canon EOS 100D rear view

The 700D's vari-angle screen is the more versatile of the two and will allow you to shoot better shots from low and high angles without any extra expense. What's more, it will save you having to kneel on the ground or get high up to compose your shots when photographing subjects at anything but eye level.

Canon EOS 700D screen