https://petapixel.com/2018/05/10/yongnuo-yn43-turns-your-phone-into-a-m4-3-mirrorless-camera/
Not bad, if it's not too expensive, opens up lots of possibilities for remote controlled cameras - provided software is customisable.
Well, it may be mirrorless but there's still that deep dark tube between the lens and the sensor.
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