so you’ve just upgraded to a Sony full frame camera, you realized your budget is pretty tight and cant afford to upgrade your lenses as well ? Just use your existing aps-c lenses in full frame mode (yes you will see vignette) but in 4k video mode you can just crop your image in post-production //
as an alternative you can use the super 35mm aps-c function or Clear image zoom on the a7iii to allow the camera to crop your sensor 1.5x …but Clear image zoom method loses out on the Focus area Features and limits the focus area to a wide center AF
the advantage of using you sony aps-c lenses on the a7iii in full frame mode allows for you to use AF features such as “Fleable spot” and “Zone” in the Focus Area menu
Vloggers beware when using aps-c lens on the A7iii without using these tips. In some cases personally I have experienced issues with the auto focus such as pulsing, which can ruin a video especially if you are only relying on the cameras AF without monitoring your image on a screen. currently I am using Andy cine’s 4k 5in. monitor with an applied zoom to crop out the vignette, frame my shots and view my images on a comfortably sized display.