Quick Tips
Select the appropriate ProRes encoding; HDR and SDR are not compatible.
An SSD drive is essential for shooting 4K ProRes Log.
Verify the compatibility and proper connection of your USB-C to USB-B cable.
Fix 1: Using an Incorrect Encoding Setting
The iPhone 15 Pro camera app, by default, won’t allow you to record in Log unless you specifically go into the settings, enable ProRes video, and choose the Log encoding. Here’s how to enable it:

Step 1: Open iPhone Settings and navigate to Camera.

Step 2: Open Camera > tap on Formats.

Step 3: In Formats, scroll down and toggle on Apple ProRes if it is currently toggled off.

Step 4: Now, tap on ProRes Encoding > choose Log.

Also Read: Apple iPhone 15 Pro Max review

Fix 2: Not Using an SSD With iPhone 15 Pro
To record Log videos in 4K or 1080P at 60fps, you must use an external SSD drive and connect it using the iPhone 15 Pro’s USB-C port.

I have been using a Samsung T7 Shield SSD with my phone, and it works well. I have also tried using Samsung’s T5 drive with it, and that works well when shooting Log on the iPhone 15 Pro models.

That said, keep the following in mind before purchasing:

Choose an external SSD only; internal 2.5” drives or M.2 drives will not work. 
All your footage will be stored directly on the SSD when you connect it to shoot Log. Therefore, invest in a drive with at least 512GB of storage. 
To shoot with the SSD, hold onto it. A rubber band can work temporarily, but consider a rig for long-term stability.
Also Read: Best external SSDs for iPhone 15 Pro series

Fix 3: Using an Incompatible Cable to Connect Your SSD
There’s a substantial data load on your SSD while writing Log video and using an incompatible USB-C to USB-C cable may result in unusable video footage. Ideally, remember the following:

We recommend using the default USB-C to USB-C cable that came in the box with your SSD.
Using an off-the-shelf cable won’t work. This results in choppy footage with missing frames.
Avoid using USB-A to USB-C adapters. In our experience, this slows down the write speed.
4. Improper Video Mode Selection
Trying to record Log video in the Cinematic mode? Well, this isn’t going to work. Apple only allows you to record ProRes Log when you are in the default Video mode. To ensure you enable Log in the Camera app, do the following:

Step 1: Open the Camera app and swipe to Video. 

Step 2: Look for ProRes Log in the top left corner, and tap on it. 

Step 3: Tap on the red record button to start filming in ProRes Log.

Fix 5: USB-C Connectivity Issues
While it’s unlikely, you may encounter this issue without noticing. I’ve experienced it myself: the large USB-C connector may not slot in properly, leading to recording interruptions. To prevent this:

When using a case, ensure the USB-C cable fits snugly without a loose connection, especially considering the case’s small bottom opening.
Ensure the cable is securely connected to the SSD drive, as prolonged use can loosen the connector, causing connectivity issues.
Note: If the cable is loose, use double-sided tape to secure it temporarily while recording onto your SSD.

FAQs
1. Can You Record ProRes Log Using an External HDD Drive?
No, you must use a compatible SSD only.

Yes, you can import Log footage directly for post-processing using the SSD; no need to copy it to your computer first.

3. Can Slow-Mo and Cinematic Videos Be Filmed in Log Encoding?
No, currently, the iPhone 15 Pro and iPhone 15 Pro Max only allow filming in Log mode within the Video mode, up to 4K at 60FPS.

Thanks for your feedback!

Guiding Tech

Why Is iPhone 15 Pro’s Log Video Not Working and How to Fix It