Full-frame sensors have no crop factor, while APS-C applies 1.5×, Four Thirds applies 2.0×, and the Sony RX10 Mark IV uses a 1-inch sensor. A 200mm lens becomes 320mm on APS-C and 400mm on Four Thirds due to crop factors.
So we'll go over each of these. So first up, we have the full-frame sensor, which is equal to 35mm film, and there is absolutely no crop on this. Next up, we've got the APS-C, which makes your 200mm lens 320mm. And on your Sony and Nikon, it's a 1.5x. So Olympus and Panasonic fall in the Four Thirds category, and they are a 2.0x crop, which makes your 200mm lens a 400mm lens. And these cameras are typically fairly small along with the lenses. Okay, so here we have the 1-inch sensor, which is what the RX10 Mark IV is.
