The rear camera systems on both phones are, by the data provided, functionally identical — a 50 MP + 2 MP dual-lens setup with matching apertures, the same 4K/30fps video ceiling, and an equivalent feature set covering phase-detection autofocus, continuous autofocus during recording, HDR, slow-motion, and manual controls for ISO, focus, exposure, and white balance. Neither offers optical image stabilization or optical zoom, so users should expect the same real-world rear shooting experience from both devices.
The only meaningful divergence in this group is the selfie camera. The Oppo A5 Pro 4G packs a 16 MP front sensor, which captures significantly more detail than the Vivo T4x 5G's 8 MP shooter — an advantage that is particularly noticeable in cropped selfies, portrait mode shots, or video calls where facial detail matters. The Vivo does respond with a marginally wider front aperture of f/2.1 versus the Oppo's f/2.4, meaning it gathers slightly more light in dim conditions. Whether that compensates for the resolution gap depends on the user's primary selfie use case — low-light performance versus daylight detail.
For most selfie-focused users shooting in typical lighting, more megapixels will have a more visible impact than a fractional aperture advantage. The Oppo A5 Pro 4G takes the edge in this group solely on the strength of its front camera resolution, while the rear systems remain a dead heat.