The Sony A7R IV has 61 million pixels, but the A7R III and A7R II can give you a taste of its performance for a lot less money
Sony Alpha 7R II Review
Sony a7R III vs a7R IV - 15 Key Differences Compared - Alpha Shooters
Sony A7R IV Review: More Megapixels, Better Autofocus, Anything Else?
Sony Alpha A7R V vs A7R IV - Amateur Photographer
Sony A7R IV Vs. A7R III Size Comparison
Sony A7R III « NEW CAMERA
Sony Announces the a7R V Mirrorless Camera; Hands on and First Look Video at B&H
Sony A7iv vs A7riii Which Should You Buy?
The Leica SL as upgrade for Sony A7R II shooters - - Filmmaking Gear and Camera Reviews
Sony A7R IV vs A7R III vs A7R II
Sony a7R V vs a7R IV: what's changed and is it worth the upgrade?: Digital Photography Review
Sony Alpha Blog : Which Lenses to maximise the potential of your Sony A7RIV/ A7RV / A1 / A7IV…?
Sony A7 IV vs A7R III / A7R IIIa - Which One is Better? - Full Comparison!
Sony A7R IV vs Sony A7R III « NEW CAMERA
Sony Camera A7 Iii, Eyecup Eyepiece, Sony A7 A7r, Eye Sony A9ii