I have never been a big fan of smartphone videography but if you are really into it and do it the right way with your iPhone, I recommend you try the Blackmagic Camera app. Blackmagic shook the industry and basically killed the business of many paid camera app creators when they launched this excellent app for iPhone for free , something that you don't see very often in iOS world.
Blackmagic Camera App v1.3
Blackmagic, mainly know by their excellent DaVinci Resolve video creation software which both have a free and paid Studio version (read How to get DavinciResolve Studio for free ) and video editing equipment, keeps on updating the Camera app with further improvements and the latest update, the V1.3 comes with number of pro-oriented features such as Audio monitoring and rack focus with supported cameras. Below you can find the full list of improvements:
Blackmagic Camera App v1.3 New Features and Impovements
Support for audio monitoring on connected earphones.
Support for rack focus controls in the camera.
Support for 48mm lens on iPhone 14 Pro and 15 Pro.
Smoother animations when switching between landscape and portrait.
Faster project listing in media tab.
Reduced latency for HDMI video feeds.
Name, reel, scene and take now display over HDMI during recording.
General performance and stability improvements.
Blackmagic Camera App
Price and Availability
Blackmagic Camera 1.3 is completely free and available to download now from the Apple App Store . Unfortunately Blackmagic doesn't offer an Android version of the app.