Apple Cinema Display shows black bars and no extended desktop with iPad Air 5

Hello world

I picked up a cheap but functional 20-inch Apple Cinema Display (the alu one). I wanted to use it as an external display for my Air 5. At home I have a basic HP screen supplied by my office which serves as an extended display but I’m away for a few months and this looked a bargain.

OK, armed with a Benfei DVI - USB C adapter, I can get the screen to mirror my iPad. But I see black bars on either side of the monitor screen. Selecting Extended Desktop in iPadOS (I’m running 27) makes no odds. I’ve connected my iPad to Magic Mouse and a Magic Keyboard. Still no luck.

Using the same cabling setup, my work laptop (HP Elitebook, Windows 11) runs an extended desktop with no issues.

Is this an adapter issue? Or just the best I’m going to get trying to make 21 year old tech work in ways it was never intended to?

Posted on Sep 22, 2026 2:04 PM

1 reply

WheelieNick

Level 9 (74,110 points)

Sep 22, 2026 2:50 PM in response to ScotsApple

This is an iPadOS limitation regarding external display aspect ratios and resolution scaling, rather than a broken adapter or a hardware failure.

Why It Happens

Aspect Ratio Mismatch: The 20-inch aluminum Apple Cinema Display has a native resolution of 1680x1050
iPadOS External Display Limits: iPadOS natively outputs external displays in standard 16:9 widescreen video resolutions (like 1080p or 4K). When connected to a 16:10 monitor like the 20-inch Cinema Display, iPadOS cannot dynamically scale its Stage Manager canvas to match the odd 1
pixel grid. Instead, it forces a 16:9 signal inside the panel, resulting in permanent black vertical pillars (bars) on the sides.
Why Windows Works: Windows 11 on your HP Elitebook queries the monitor's EDID (Extended Display Identification Data), recognizes 1
natively, and adjusts the graphics output to fill the exact pixel layout. iPadOS lacks this granular, legacy non-standard resolution matching for older external monitors.