I want my live streams to look better. How can I connect several iPads and iPhones to create a multi-camera studio setup?

You can turn several iPhones and iPads into a surprisingly capable multi-camera studio. The basic idea is:

iPhones/iPads = cameras → network or USB → switching software → livestream platform

A common setup looks like this:

iPhone Camera 1 (wide shot) ┐
iPhone Camera 2 (close-up)  ├──> OBS Studio / Switcher → YouTube/Twitch/etc.
iPhone Camera 3 (overhead) ┘
             |
        iPad control screen (optional)

Camera for OBS Studio Apple Apps## Option 1: Use OBS Studio (most flexible)

This is the setup I’d choose for a serious studio.

What you need

• 2–5 iPhones/iPads as cameras
• A Mac or PC running OBS Studio
• Camera apps that send video to OBS
• Tripods/clamps
• Good lighting
• External microphone/audio interface (usually better than camera audio)

Camera connections

Best: USB

• Connect each iPhone/iPad to the computer with a data cable.
• Add each device as a separate camera source in OBS.
• USB usually gives lower delay and fewer dropouts than Wi-Fi.Camera for OBS Studio

Wireless: NDI over Wi-Fi

• Put all devices and the computer on the same network.
• Use an NDI camera app on each iPhone/iPad.
• Add each feed as an NDI source in OBS.Camera for OBS Studio+1

A practical layout:

• Camera 1: wide room shot
• Camera 2: presenter/host close-up
• Camera 3: desk, product, instrument, or overhead shot
• Camera 4: guest angle or backup

Option 2: Use an iPad as the switcher

If you want a compact “no laptop” workflow, apps such as Switcher Studio are designed around using iPhones/iPads as multiple cameras with an iPad as the control surface.Apple Apps

Typical layout:

iPhone → Camera angle 1
iPhone → Camera angle 2
iPhone → Camera angle 3
          ↓
       iPad switcher
          ↓
     Livestream

This is convenient for:

• podcasts
• classrooms
• churches/events
• product demos
• small productions

Make it look like a real studio

The cameras are only part of the upgrade.

1. Lock your cameras

On each device:

• lock exposure
• lock focus
• disable auto white balance if possible
• use the rear camera, not the selfie camera

A consistent image looks much more professional.

2. Add real lighting

A cheap lighting upgrade often improves quality more than buying another camera.

Basic three-light setup:

• Key light: your main face light
• Fill light: softer light from the other side
• Back light: separates you from the background

3. Use one good audio source

Avoid switching between phone microphones.

Better:

• USB microphone into the computer
• wireless lav mic
• audio interface + XLR microphone

Then let OBS use that single audio track while cameras only provide video.

4. Create scenes

In OBS, build scenes like:

• Starting Soon
• Full camera
• Two-person split screen
• Screen share + face cam
• Product close-up
• Ending screen

You can switch instantly while live.

A simple starter build

Budget setup

• 2 old iPhones
• 1 iPad
• OBS Studio
• USB cables
• Small tripods
• One good microphone
• Two LED lights

Higher-quality setup

• 3–4 iPhones
• Wired USB connections
• Dedicated audio interface
• Ethernet-connected computer
• Stream controller for switching

One tip: don’t mix too many connection methods at first. Three USB-connected phones will usually be easier to manage than a mix of USB, Bluetooth, and Wi-Fi cameras.Camera for OBS Studio+1

If you tell me what you stream (gaming, podcast, music, teaching, products, fitness, etc.), how many iPhones/iPads you have, and whether you use Mac, Windows, or only iPads, I can suggest a specific wiring diagram and gear list.

• 2 old iPhones
• 1 iPad
• OBS Studio
• USB cables
• Small tripods
• One good microphone
• Two LED lights

Higher-quality setup

• 3–4 iPhones
• Wired USB connections
• Dedicated audio interface
• Ethernet-connected computer
• Stream controller for switching

One tip: don’t mix too many connection methods at first. Three USB-connected phones will usually be easier to manage than a mix of USB, Bluetooth, and Wi-Fi cameras.

Setting up a multi-camera live streaming studio using your existing iPhones and iPads is entirely wireless, incredibly flexible, and produces a remarkably professional look.

Watch this quick overview to see how multiple iOS devices can seamlessly connect for a multi-cam setup:

0:41Multi camera Q&A livestream using iPhone and iPadYouTube · Detail · 1.3K views · 7 months ago

1. Choose Your Multi-Camera Software (The Switcher Hub)

You need a central app running on a primary device (like an iPad or Mac) that acts as your switcher, while your other iPhones and iPads act as wireless remote camera angles. Top options include:apps.apple.com+1

• Switcher Studio: The gold standard for iOS-only multi-cam setups. It allows you to connect multiple iPhones and iPads, switch angles in real-time, add custom graphics/overlays, and stream directly to platforms like YouTube or Facebook.youtube.com+1
• Detail: A fantastic, user-friendly app that lets you link multiple iOS devices instantly via a local connection to mix angles and record or stream on the fly.youtube.com
• Riverside / Restream: Great if you prefer a cloud-hosted studio approach where each device joins your virtual studio as a separate participant.

2. Essential Hardware Checklist

To make your mobile studio look and feel professional, you'll want a few supportive accessories:

• Sturdy Tripods & Mounts: Secure every iPhone and iPad onto reliable tripods with robust smartphone/tablet clamp mounts so your angles stay locked and steady.
• Consistent Lighting: Mobile sensors struggle in dim environments. Invest in softbox lights or ring lights to keep your video clean and noise-free.
• Dedicated Audio Source: Don’t rely on built-in device mics. Plug a wireless lavalier or USB microphone (like a Rode or Shure mic) into your main switching device or audio interface for pristine sound.

3. Step-by-Step Connection Guide

1. Connect to Wi-Fi: Ensure all your iPhones and iPads are hooked up to the exact same strong, stable Wi-Fi network (or create a dedicated local router network if you are on location).
2. Install and Launch: Download your chosen streaming app (e.g., Switcher Studio or Detail) across all participating devices.
3. Designate Roles: Choose one powerful iPad or Mac to be your Switcher/Director monitor. Set all other iPhones and iPads as Camera Inputs.
4. Pair the Devices: Open the app on your main switcher, go to the camera/inputs tab, and pair the secondary iPhones and iPads over the local network.
5. Optimize Camera Settings: On each remote iOS device, flip to the rear-facing camera (for higher resolution), lock your exposure/focus so it doesn't hunt in real-time, and frame your shots (e.g., Wide Angle, Tight/Close-up, Side Profile).switcherstudio.com+3

If you'd like to narrow this down, let me know:

• Which streaming platform(s) you plan to broadcast to (YouTube, Twitch, LinkedIn, etc.)
• Whether you have a preferred app in mind or want help choosing the best subscription/free tier for your budget

Transforming multiple iPhones and iPads into a wireless, multi-camera production studio is entirely doable and yields a remarkably clean, high-end look without messy HDMI capture cards or heavy hardware switchers.youtube.com+2

To see how seamlessly a multi-device setup functions in a real environment, watch this overview of mobile-based production workflows:

1mEasily Create PROFESSIONAL Live Streams Using Your iPadYouTube · Teaching With Intelligence · 9.5K views · 1 year ago

1. Choose Your Multi-Camera Software Hub

You need an app ecosystem that acts as the "switcher" on a primary device (usually an iPad acting as your control room) while connecting your other iPhones and iPads wirelessly as remote camera angles. Top choices include:youtube.com+1

• Switcher Studio: The gold standard for iOS-only multi-cam setups. It turns one main iPad into a production switcher where you can direct, cut between up to 9 devices, add graphics/logos, and stream directly to platforms like YouTube, Facebook, or custom RTMP destinations.youtube.com+1
• Detail: A fantastic, streamlined option if you want a modern, user-friendly interface to link a couple of iOS devices together quickly for a cable-free experience.youtube.com+1
• Riverside: Great if your live stream involves remote recording or an interview format where you want local multi-device control and cloud streaming integration.

2. Follow These Setup Steps

1. Connect to a Strong, Shared Wi-Fi: Ensure all participating iPhones and iPads are connected to the exact same high-speed Wi-Fi network (or create a dedicated local router network/hotspot setup for reliability).
2. Designate Your Switcher: Open your chosen app (e.g., Switcher Studio) on your main iPad. This will be your director's monitor and control dashboard.
3. Pair Secondary Cameras: Open the app on your other iPhones and iPads. In your main iPad switcher, look for available local sources and tap to add/pair each device. They will instantly feed their live view back to your master iPad.
4. Configure Camera Orientations & Settings: Flip your iPhones/ iPads into landscape mode (unlock rotation), lock your focus and exposure manually within the app so they don't hunt for light mid-stream, and position the rear (higher-quality) lenses facing your subjects.
5. Manage Your Audio: Route your audio cleanly. Do not use the raw built-in microphone of every single phone—instead, plug a dedicated wireless mic system (like a Rode Wireless or DJI Mic) or a USB audio interface directly into your main switcher iPad or primary audio source.
6. Go Live: Add your titles, lower-thirds, or split-screen layouts inside the control app, plug in your destination stream keys (YouTube, Twitch, LinkedIn, etc.), and hit go live from your central iPad.youtube.com+5

Essential Hardware Add-Ons

• Sturdy Tripods & Mounts: Use secure phone/iPad clamps with standard 1/4-inch thread mounts to keep every angle rock-solid.youtube.com+2
• Continuous Lighting: Mobile sensors need good light to look professional. Two softbox lights or panel lights will eliminate grain and make your multi-cam footage pop.youtube.com+2
• Power Management: Streaming taxes battery life quickly. Plug your devices into long lightning/USB-C cables or external power banks if you're streaming for more than an hour.

If you want to narrow this down, tell me:

• Which streaming platform(s) are you targeting (YouTube, Twitch, TikTok, etc.)?
• Do you already have an external microphone or audio interface , or do you need recommendations there too?

Absolutely. You can build a surprisingly good multi-camera live-streaming studio using several iPhones/iPads, with a Mac acting as the production switcher. The key is to treat the Apple devices as cameras and send all feeds into one central production system.

The setup I'd recommend

 iPhone #1 ──┐
 iPhone #2 ──┤
 iPhone #3 ──┼──► Mac ──► OBS Studio ──► YouTube/Twitch/etc.
 iPad #1 ────┘        │
                      ├──► Microphone/audio interface
                      └──► Graphics / overlays / music

1. Use the iPhones as your cameras

There are two main approaches:

Best/easiest: use an app such as Camo to turn each iPhone into a camera source for the Mac. OBS's own smartphone guide supports Camo and notes that it can connect over USB or Wi-Fi.OBS Studio

More advanced: use NDI. An NDI-capable iPhone app sends each camera over your local network, and OBS can receive the individual feeds. OBS specifically documents NDI HX Camera as an option for this.OBS Studio+1

For a serious studio, I'd favor wired USB wherever possible. Wireless cameras are convenient, but Wi-Fi congestion can introduce latency or dropped frames.

2. Put OBS on a Mac

Use OBS Studio as your control room.

Create a scene for each shot:

• Camera 1: wide establishing shot
• Camera 2: close-up of you
• Camera 3: side angle / second presenter
• iPad: overhead/desk/product shot
• Screen capture: computer/iPad presentation
• "BRB" scene: standby graphic

You can then switch between cameras during the stream rather than broadcasting one static shot.

OBS officially supports smartphones as camera sources, including multiple-device workflows.OBS Studio

3. An iPad can be particularly useful

I'd actually use an iPad as an overhead camera or secondary production device, rather than making every device identical.

For example:

           iPhone 1
          [Presenter]
              ↓
   iPhone 2 → YOU ← iPhone 3
              ↑
         iPad overhead
          [Desk/table]

That gives you four visually different angles without needing expensive cameras.

4. Don't rely on AirPlay for everything

Apple's Continuity/AirPlay features are useful, but they're not really a complete multi-camera production system. Continuity Camera officially turns an iPhone into a Mac webcam, and Apple supports both wireless and USB connections.Apple Support+1

The important distinction is:

Continuity Camera = great for getting an iPhone into the Mac as a camera.

NDI/Camo + OBS = better foundation for deliberately building a multi-camera studio.

Apple also notes that Continuity Camera is designed around using an iPhone with a Mac, so I wouldn't plan the entire studio around trying to make iPads and iPhones behave like a conventional hardware video switcher.Apple Support

The thing that will make the biggest difference: audio

Don't use the microphones on every phone and try to mix them together.

Instead:

One good microphone → audio interface/mixer → Mac → OBS

For example:

        🎤 Mic
          ↓
   Audio interface
          ↓
        Mac
          ↓
   ┌──────┴──────┐
 Cameras       OBS
   ↓             ↓
   └────────► Live stream

That gives you consistent audio while you switch cameras.

Make the cameras look like a real studio

A few inexpensive additions make a huge difference:

• Put every iPhone/iPad on a proper tripod or desk mount.
• Shoot in landscape.
• Lock exposure and focus where possible.
• Keep the color temperature consistent between cameras.
• Use one large soft key light rather than relying on room lighting.
• Add a smaller fill/rim light if needed.
• Keep the cameras at approximately eye level for your main shots.
• Use the rear cameras rather than selfie cameras when practical.

Apple's own guidance recommends mounting an iPhone securely in landscape orientation when using it as a camera.Apple Support

A really nice "starter studio"

If you already own several Apple devices, I'd build it like this:

Then create OBS scenes that combine those feeds with your branding, lower thirds, comments, graphics, music, etc.

One important upgrade

If you're planning to have 3–5 cameras running simultaneously, I'd put the Mac on Ethernet and give the cameras a strong dedicated Wi-Fi network—or use USB for the cameras that can be wired.

That will make the system substantially more reliable than having five devices fighting for bandwidth on an ordinary household Wi-Fi network.

If you tell me which iPhone/iPad models you have, whether you have a Mac (and which model), and whether you're streaming to YouTube, Twitch, Facebook, or somewhere else, I can lay out the exact setup—including the apps, cables, mounts, networking, OBS scenes, and a sensible budget.

Apple also notes that Continuity Camera is designed around using an iPhone with a Mac, so I wouldn't plan the entire studio around trying to make iPads and iPhones behave like a conventional hardware video switcher.Apple Support

The thing that will make the biggest difference: audio

Don't use the microphones on every phone and try to mix them together.

Instead:

One good microphone → audio interface/mixer → Mac → OBS

For example:

        🎤 Mic
          ↓
   Audio interface
          ↓
        Mac
          ↓
   ┌──────┴──────┐
 Cameras       OBS
   ↓             ↓
   └────────► Live stream

That gives you consistent audio while you switch cameras.

Make the cameras look like a real studio

A few inexpensive additions make a huge difference:

• Put every iPhone/iPad on a proper tripod or desk mount.
• Shoot in landscape.
• Lock exposure and focus where possible.
• Keep the color temperature consistent between cameras.
• Use one large soft key light rather than relying on room lighting.
• Add a smaller fill/rim light if needed.
• Keep the cameras at approximately eye level for your main shots.
• Use the rear cameras rather than selfie cameras when practical.

Apple's own guidance recommends mounting an iPhone securely in landscape orientation when using it as a camera.

A really nice "starter studio"

If you already own several Apple devices, I'd build it like this:

Setting up a multi-camera studio using your existing iPhones and iPads is one of the best ways to dramatically boost your production value without buying expensive broadcast hardware.

Here is how you can connect your iOS devices into a seamless multi-camera production studio.

1. Choose a Multi-Cam Switcher App

You will need a specialized iOS application that connects your devices via a local Wi-Fi network. One device acts as the "switcher" (the director control room where you tap to change angles), and the others act as wireless remote cameras. Top options include:youtube.com+1

• Switcher Studio: The gold standard for iOS-only multi-cam production. It lets you connect up to 9 iPhones or iPads, add custom graphics, overlays, and brand kits, and stream directly to platforms like YouTube, Facebook, or RTMP destinations.youtube.com+2
• Detail: A fantastic, user-friendly app that makes linking multiple iPhones/iPads or a mix of iOS and Mac devices straightforward for multi-angle streams and Q&As.youtube.com+1
• OBS Camera / Camo: If you prefer routing your mobile device feeds into a computer-based setup (like OBS Studio or Ecamm Live), you can connect your iPhones/iPads as wireless or wired webcam inputs.

2. Prepare Your Network and Hardware

• Wi-Fi Stability: Ensure all your iPhones and iPads are connected to the same strong, low-latency Wi-Fi network (preferably 5GHz or a dedicated high-speed router). If Wi-Fi congestion is an issue, some apps support hardwired Ethernet adapters for iPads or direct USB-C/Lightning tethering.youtube.com+1
• Mounting and Power: Put your secondary cameras on sturdy tripods with reliable phone/tablet mounts. Because streaming drains battery quickly, plug your devices into long lightning/USB-C power cables or portable power banks.
• Use the Rear Cameras: Always frame your shots using the rear-facing cameras on your iPhones and iPads, as they offer significantly higher sensor quality than the selfie cameras.

3. Optimize Audio and Settings

• Dedicated Audio Source: Don't rely on the built-in microphone of a camera that's sitting far away on a tripod. Plug a dedicated wireless mic (like a Rode Wireless GO or DJI Mic ) into your main switcher device or an audio interface, and mute the audio inputs on your secondary remote camera devices to avoid echo.
• Lock Exposure and Focus: Manual exposure and focus lock prevent your cameras from annoyingly "hunting" for light or focus mid-stream if you move around.

Would you like help deciding between streaming directly from an iPad app vs. routing your iPhones into a computer setup like OBS , or do you need recommendations for microphones and lighting?

Turning your iPhones and iPads into a multi-camera live streaming studio is a cost-effective way to get high-production value without buying bulky broadcast hardware.

Here are the best methods and software tools to connect your iOS devices into a seamless multi-cam setup:

Method 1: All-in-One iOS Production Apps (Easiest & Wireless)

Dedicated apps allow you to use one iPad/iPhone as the main "switcher/director" console and the other devices as wireless remote camera angles over a strong local Wi-Fi network.

• Switcher Studio: This is the industry standard for iOS multi-cam setups. You install the app on all devices, designate one iPad as the master switcher, and connect up to 9 iPhones/iPads as wireless video sources. It lets you switch angles live, insert graphics/logos, add pre-recorded video, and stream straight to platforms like YouTube or Facebook.youtube.com+2
• Detail App: A fantastic, lightweight option if you want a clean multi-cam setup (like a podcast or Q&A) using just a couple of iOS devices. You simply open the app on your devices, pair them together via the connection menu, and you can switch angles or stream directly to platforms like YouTube and Twitch without dealing with wires.youtube.com+1

Check out how easy a quick wireless two-device setup is in this tutorial:

Watch this short guide on setting up a multi-cam Q&A stream using iOS devices:

0:41Multi camera Q&A livestream using iPhone and iPadYouTube · Detail · 1.3K views · 6 months ago

Method 2: NDI Video over Wi-Fi (For OBS Studio / Desktop Switchers)

If you prefer routing your iPhone and iPad camera feeds into a computer running OBS Studio, Wirecast , or Ecamm Live , you can use NDI (Network Device Interface) technology.

1. Download an NDI camera app (such as NDI HX Camera ) on each of your iPhones and iPads.
2. Ensure your computer and all iOS devices are connected to the same high-speed Wi-Fi network (or hardwired via Ethernet/adapters for ultimate stability).
3. Open OBS Studio on your computer with the OBS-NDI plugin installed. Your iPhones and iPads will automatically pop up as network video sources that you can assign to different scenes or angles.

Method 3: Apple Ecosystem / Final Cut Setup

If you are editing or monitoring your live workflow via an iPad and have newer hardware:

• You can utilize apps like Apple's Final Cut Camera app on your secondary iPhones to feed clean signals directly into a main production app or a compatible iPad running professional production suites.

Essential Tips for a Stable Multi-Cam iOS Studio

• Network Stability is King: Wireless multi-cam streaming relies heavily on your local network. Use a robust 5GHz Wi-Fi router, or keep your primary director device hardwired using a Lightning/USB-C to Ethernet adapter if possible.
• Lighting and Audio: Mobile sensors look incredible in good light, so invest in softbox lights or ring lights. More importantly, do not rely on built-in device mics . Plug a dedicated USB or wireless mic (like a Rode Wireless GO or DJI Mic ) into your main switcher or audio interface.
• Power Management: Streaming over Wi-Fi while utilizing the camera sensor will drain batteries fast. Mount your iPhones and iPads using clamped stands that allow you to plug in continuous external power via long Lightning or USB-C cables.youtube.com+2

To help narrow down the best workflow, tell me:

• What streaming platform(s) are you planning to broadcast to?
• Do you want to use a computer (like a Mac or PC) as your main control room, or do everything entirely from an iPad?

Yes. The cleanest way to turn several iPhones/iPads into a multi-camera live-stream studio is to use the Apple devices as cameras, bring their feeds into one Mac, and use streaming software to switch between them.

One important distinction: Apple’s built-in Continuity Camera is excellent for using an iPhone as a Mac webcam, but it is designed around one iPhone and one Mac at a time, so it isn't by itself a multi-camera switcher.Apple Support+1

A setup I'd recommend

iPhone #1 ──┐
iPhone #2 ──┤
iPhone #3 ──┼──> Mac ──> OBS / streaming software ──> YouTube/Twitch/etc.
iPad #1 ────┘             ↑
                          │
                    USB / network

1. Use the iPhones as dedicated cameras

Give each device a job:

• Camera 1: main talking-head/wide shot
• Camera 2: close-up or alternate angle
• Camera 3: overhead/product/demo shot
• iPad: presentation, notes, screen/demo, or an additional wide shot

Mount everything on tripods or desk arms and keep the devices plugged into power. Apple supports Continuity Camera over either Wi-Fi or USB, with USB being preferable when you want reliable connectivity and continuous charging.Apple Support+1

2. For a serious setup, use wired connections

If you're streaming for hours, I'd avoid relying entirely on Wi-Fi.

A good architecture is:

iPhones → USB → Mac → streaming software → internet

That reduces the possibility of Wi-Fi congestion causing a camera to freeze or disappear.

If you have newer iPhones with USB-C, this becomes considerably easier. You can also use powered USB hubs/docks, although you need to make sure the Mac and hub have enough bandwidth and power for all the cameras.

3. Use streaming/switching software

This is where the studio actually comes together.

OBS Studio is a particularly good choice because you can create scenes such as:

• 🎥 Main camera
• 🎥 Two-camera split screen
• 🖥️ Camera + presentation
• 📦 Overhead/product camera
• 💬 Camera + comments/graphics

Then you can switch scenes while you're live.

You can also add your microphone, music, lower-thirds, logos, alerts, screen captures and other graphics in the same place.

4. Don't use the iPhone microphones

For a noticeably more professional stream, make one microphone your master audio source.

For example:

                    ┌─ iPhone 1
                    ├─ iPhone 2
Microphone ──> Mac ─┼─ iPhone 3
                    └─ iPad
                         ↓
                       OBS
                         ↓
                     Livestream

The cameras provide video only. Your microphone/interface provides the audio.

That prevents the classic livestream problem where switching cameras also changes the sound.

What I'd build at three different budgets

Simple / inexpensive

2–3 iPhones + Mac + OBS + USB/Wi-Fi

Great if you already own the devices.

Use:

• Existing iPhones
• Tripods
• USB cables
• Mac
• OBS
• One good microphone

This can look surprisingly professional because modern iPhone cameras are very capable.

Better studio

3 iPhones + 1 iPad + Mac + wired connections + dedicated microphone/interface + lighting

I'd add:

• Key light
• Fill/background light
• Consistent camera exposure/white balance
• Powered USB hub/dock
• Ethernet connection for the Mac
• Dedicated audio interface
• Headphones

The lighting upgrade can actually make a bigger difference than buying another camera.

Professional / permanent studio

I'd eventually move toward:

Cameras → capture/network system → hardware/software switcher → streaming computer

At that point your iPhones can still be useful as specialty cameras, but dedicated cameras become easier to manage for exposure, lenses, power, and long-running reliability.

One Apple-specific wrinkle

Apple's Continuity Camera officially supports using an iPhone XR or newer with a Mac running macOS Ventura 13 or later, and it can operate wirelessly or over USB.Apple Support

But if your goal is three or four simultaneous camera feeds, I wouldn't design the whole studio around Continuity Camera alone. You want a camera-ingest solution that can expose multiple independent video sources to your streaming software.

If you tell me which iPhones/iPads you have, which Mac you have, and whether you're streaming to YouTube, Twitch, Facebook, Zoom, etc., I can map out the exact setup—including cables/adapters, camera apps, OBS scenes, audio, lighting, and how to switch cameras live.

The cameras provide video only. Your microphone/interface provides the audio.

That prevents the classic livestream problem where switching cameras also changes the sound.

What I'd build at three different budgets

Simple / inexpensive

2–3 iPhones + Mac + OBS + USB/Wi-Fi

Great if you already own the devices.

Use:

• Existing iPhones
• Tripods
• USB cables
• Mac
• OBS
• One good microphone

This can look surprisingly professional because modern iPhone cameras are very capable.

Better studio

3 iPhones + 1 iPad + Mac + wired connections + dedicated microphone/interface + lighting

I'd add:

• Key light
• Fill/background light
• Consistent camera exposure/white balance
• Powered USB hub/dock
• Ethernet connection for the Mac
• Dedicated audio interface
• Headphones

The lighting upgrade can actually make a bigger difference than buying another camera.

Professional / permanent studio

I'd eventually move toward:

Cameras → capture/network system → hardware/software switcher → streaming computer

At that point your iPhones can still be useful as specialty cameras, but dedicated cameras become easier to manage for exposure, lenses, power, and long-running reliability.

One Apple-specific wrinkle

Apple's Continuity Camera officially supports using an iPhone XR or newer with a Mac running macOS Ventura 13 or later, and it can operate wirelessly or over USB.

But if your goal is three or four simultaneous camera feeds, I wouldn't design the whole studio around Continuity Camera alone. You want a camera-ingest solution that can expose multiple independent video sources to your streaming software.