PS4 to iMac Display using Kanex Converter

Hi,

I've got a mid 2010 27" iMac that I'm keen to use as a display for my PS4.

I have a Kanex XD HDMI to Mini DisplayPort Converter for Apple iMac 27; see link below.

Its all connected up but when I try to go to target mode (Command + F2), there's no response?

Any suggestions would be appreciated!

Cheers

https://www.amazon.co.uk/d/att/Kanex-HDMI-Mini-DisplayPort-Converter-Apple-scree n/B003LGOWNQ